Merge pull request #135 from bvssvni/master

Upgraded to latest Rust-Empty
Merge pull request #137 from bvssvni/master

Added `col_mat3x2_mul_col`
Merge pull request #138 from bvssvni/master

Fixed ambigious comment
Merge pull request #139 from bvssvni/master

Added `col_mat4x3_mul_col`
Merge pull request #140 from bvssvni/master

Added `row_mat4_mul_row`
Merge pull request #141 from bvssvni/master

Added `col_mat4_mul_col`
Merge pull request #142 from bvssvni/master

Added `col_mat3x2_mul`
Merge pull request #143 from bvssvni/master

Added `col_mat4x3_mul`
Merge pull request #144 from bvssvni/master

Added `row_mat3_mul`
Merge pull request #145 from bvssvni/master

Added `col_mat3_mul` and `col_mat3_mul_col`
Merge pull request #146 from bvssvni/master

Added `row_mat4_mul`
Merge pull request #147 from bvssvni/master

Added `col_mat4_mul`
Merge pull request #148 from bvssvni/master

Fixed bug in `mat4_id`
Add Travis CI
Merge pull request #149 from Indiv0/add-travis-ci

Add Travis CI
Added col_mat4_transform

Closes https://github.com/PistonDevelopers/vecmath/issues/150