Fixed GLSL shaders compilation errors on OS X

Fixed "'input' : Reserved word." in several shaders
Fixed "'*' does not operate on 'float' and 'int'" in GlitchRows shader
Fixed "Incompatible types in initialization (and no available implicit conversion)" in ShieldPulse shader
Fixed "No matching function for call to pow(float, int)" in ShieldWarp shader
Merge pull request #7 from alexey-lysiuk/fix_shaders_osx

Fixed GLSL shaders compilation errors on OS X