Merge pull request #30 from hisohito/master

Code documentation
fixes #26
added asSource methods into default classes
fixes #32
minor changes
removed unused import
fixes #31
documented Matrices class a bit
documented a bit
documentation improvements
fixes #28
fixes #29
cleaned a code a bit
fixes #14
added missid abs for test
fixes #36
added slice method for vectors
added missed sliceLeft and sliceRight
fixes #35
fixes #33