Added Quat4d
Consistent naming of Quat and Vector classes
Merge pull request #12 from msteiger/quat4d

Added Quat4d
Added Matrix3d class
Changed emptry abstract methods to get(row, col)

This reduces the number of methods that must be implemented from 9 to 1
Implementing an array-based matrix is thus easily possible.
Implementation based on member are not affected.
Added Matrix3d tests
Merge branch 'master' into tuple2i