Merge branch 'release/0.0.15'
src: fixed a problem in GCC
Merge branch 'hotfix/0.0.15'
src: fixed a problem in GCC
Merge branch 'master' into develop
src: added class method 'Matrix.Identity()'
test: added 'Matrix.Identity()' testing
readme: added 'Matrix.Identity()' api
added class method 'Matrix.Identity()'