Component wise multiplication and division

Had to rename the max and min functions due to conflicts with other libraries and used the prefix km as in all other functions. 

Added component wise multiplication and division. 

Also added operators for the c++ classes ( += , -= , *=, /= ). From my point of view, the overloaded operator * in the C++ that does the dot product should perform the component wise multiplication, more in line with what happens in GLSL, and use a static dot function inside the class. But, I guess that making that change would break code using the library, and I didn't touch it.  

Also moved the .h files for kazmathxx outside the src directory. That is weird when you have to make an : 
#include <kathmath/src/vec2.h>