diff --git a/SConstruct b/SConstruct
index 45e48478..8d3ee649 100644
--- a/SConstruct
+++ b/SConstruct
@@ -34,6 +34,8 @@ build('src/librender/SConscript')
 build('src/libhw/SConscript')
 # Bidirectional support library
 build('src/libbidir/SConscript')
+# Python binding library
+build('src/libpython/SConscript')
 
 # ===== Build the applications =====
 env = env.Clone()
@@ -49,9 +51,6 @@ build('src/mtsgui/SConscript', ['mainEnv', 'converter_objects'], duplicate=True)
 
 env['SHLIBPREFIX']=''
 
-# Python binding library
-build('src/mtspy/SConscript')
-
 # ===== Build the plugins =====
 
 Export('env')
diff --git a/build/SConscript.install b/build/SConscript.install
index fe074257..7fe30d39 100644
--- a/build/SConscript.install
+++ b/build/SConscript.install
@@ -43,7 +43,7 @@ if sys.platform == 'linux2':
 	install(distDir, ['libcore/libmitsuba-core.so', 'libhw/libmitsuba-hw.so',
 			'librender/libmitsuba-render.so', 'libbidir/libmitsuba-bidir.so'])
 	if hasPython:
-		install(distDir, ['mtspy/mtspy.so'])
+		install(os.path.join(distDir, 'mitsuba.so'), ['libpython/mitsuba.so'])
 	install(distDir, ['mitsuba/mitsuba', 'mitsuba/mtssrv', 'mitsuba/mtsutil', 'mtsgui/mtsgui'])
 	if hasCollada:
 		install(distDir, ['converter/mtsimport'])
@@ -70,7 +70,7 @@ if sys.platform == 'win32':
 	install(distDir, ['libcore/libmitsuba-core.dll', 'libhw/libmitsuba-hw.dll',
 			'librender/libmitsuba-render.dll', 'libbidir/libmitsuba-bidir.dll'])
 	if hasPython:
-		installAs(os.path.join(distDir, 'mtspy.pyd'), 'mtspy/mtspy.dylib')
+		installAs(os.path.join(distDir, 'python/mitsuba.pyd'), 'libpython/mitsuba.dll')
 	install(distDir, ['Iex.dll', 'Half.dll','IlmThread.dll', 'Imath.dll','IlmImf.dll','zlib1.dll',
 		'libpng13.dll',	'jpeg62.dll', 'pthreadVCE2.dll', 'xerces-c_3_0.dll', 'glew32mx.dll'],
 		prefix=dllprefix)
@@ -115,7 +115,7 @@ elif sys.platform == 'darwin':
 	install(frameworkDir, ['libcore/libmitsuba-core.dylib', 'libhw/libmitsuba-hw.dylib',
 		'librender/libmitsuba-render.dylib', 'libbidir/libmitsuba-bidir.dylib'])
 	if hasPython:
-		installAs(os.path.join(frameworkDir, 'mtspy.so'), 'mtspy/mtspy.dylib')
+		installAs(os.path.join(distDir, 'python/mitsuba.so'), 'libpython/mitsuba.dylib')
 	install(frameworkDir, [
 		'GLEW.framework/Resources/libs/libGLEW.dylib', 'OpenEXR.framework/Resources/lib/libHalf.6.dylib',
 		'OpenEXR.framework/Resources/lib/libIex.6.dylib', 'OpenEXR.framework/Resources/lib/libImath.6.dylib',
diff --git a/include/mitsuba/core/matrix.h b/include/mitsuba/core/matrix.h
index 0b4cef50..7601b3e9 100644
--- a/include/mitsuba/core/matrix.h
+++ b/include/mitsuba/core/matrix.h
@@ -187,6 +187,14 @@ public:
 		return *this;
 	}
 
+	/// Matrix-scalar addition
+	inline const Matrix &operator-=(T value) {
+		for (int i=0; i<M; ++i)
+			for (int j=0; j<N; ++j)
+				m[i][j] -= value;
+		return *this;
+	}
+
 	/// Component-wise negation
 	inline Matrix operator-() const {
 		Matrix result;
diff --git a/src/mtspy/SConscript b/src/libpython/SConscript
similarity index 63%
rename from src/mtspy/SConscript
rename to src/libpython/SConscript
index ab4c9ab3..706d2e9f 100644
--- a/src/mtspy/SConscript
+++ b/src/libpython/SConscript
@@ -11,8 +11,4 @@ if pythonEnv.has_key('PYTHONLIB'):
 	pythonEnv.Prepend(LIBS=pythonEnv['PYTHONLIB'])
 
 if hasPython:
-	mtspy_plugin = pythonEnv.SharedLibrary('mtspy', ['base.cpp']);
-	#mtspy_app = pythonEnv.SharedLibrary('mtspy', ['base.cpp']);
-
-	if sys.platform == "darwin":
-		pythonEnv.AddPostAction(mtspy_plugin, 'install_name_tool -id @loader_path/mtspy.dylib $TARGET')
+	libpython = pythonEnv.SharedLibrary('mitsuba', ['base.cpp']);
diff --git a/src/mtspy/base.cpp b/src/libpython/base.cpp
similarity index 98%
rename from src/mtspy/base.cpp
rename to src/libpython/base.cpp
index a714019e..4001d739 100644
--- a/src/mtspy/base.cpp
+++ b/src/libpython/base.cpp
@@ -90,9 +90,7 @@ void export_core() {
 		.def("getRefCount", &Object::getRefCount)
 		.def("__str__", &Object::toString);
 	
-	bp::class_<Stream, ref<Object>, bp::bases<Object>, boost::noncopyable>("Stream", bp::no_init)
-		.def("getRefCount", &Object::getRefCount)
-		.def("__str__", &Object::toString);
+	bp::class_<Stream, ref<Stream>, bp::bases<Object>, boost::noncopyable>("Stream", bp::no_init);
 
 	bp::enum_<Stream::EByteOrder>("EByteOrder")
 		.value("EBigEndian", Stream::EBigEndian)
@@ -341,7 +339,6 @@ void export_core() {
 		.def("__setitem__", &Matrix4x4_setItem)
 		.def("__getitem__", &Matrix4x4_getItem)
 		.def("setIdentity", &Matrix4x4::setIdentity)
-		.def("setZero", &Matrix4x4::setZero)
 		.def("isZero", &Matrix4x4::isZero)
 		.def("trace", &Matrix4x4::trace)
 		.def("det", &Matrix4x4::det)
diff --git a/src/mtspy/mtspy.h b/src/libpython/mtspy.h
similarity index 100%
rename from src/mtspy/mtspy.h
rename to src/libpython/mtspy.h