docs / clenup (no functional code changes)

- added API examples for mathutils.Color/Euler/Quaternion/Matrix.
- corrected own bad spelling matricies --> matrices.
- minor pep8 edits.
- update CMake ignore file list.

doc/python_api/examples/mathutils.Matrix.py

@@ -1,3 +1,28 @@
 import mathutils
+import math
 
-# todo
+# create a location matrix
+mat_loc = mathutils.Matrix.Translation((2.0, 3.0, 4.0))
+
+# create an identitiy matrix
+mat_sca = mathutils.Matrix.Scale(0.5, 4, (0.0, 0.0, 1.0))
+
+# create a rotation matrix
+mat_rot = mathutils.Matrix.Rotation(math.radians(45.0), 4, 'X')
+
+# combine transformations
+mat_out = mat_loc * mat_rot * mat_sca
+print(mat_out)
+
+# extract components back out of the matrix
+loc, rot, sca = mat_out.decompose()
+print(loc, rot, sca)
+
+# it can also be useful to access components of a matrix directly
+mat = mathutils.Matrix()
+mat[0][0], mat[1][0], mat[2][0] = 0.0, 1.0, 2.0
+
+mat[0][0:3] = 0.0, 1.0, 2.0
+
+# each item in a matrix is a vector so vector utility functions can be used
+mat[0].xyz = 0.0, 1.0, 2.0