Math optimizations

[smilediver]

Mostly moves some trivial and commonly used methods in math classes to headers so that they can be inlined by compiler.

[paulocoutinhox]

What is inl file?

[halx99]

I prefer just implement inline APIs in class define directly, don't create individual .inl file if the inline APIs are public

[smilediver]

Should I put definitions with declarations like so:

class Color {
    void method() { doStuff(); }
};

or keep declarations clean and put definitions at the end of file like this:

class Color {
    void method();
};

void Color::method() { doStuff(); }

or maybe something in between, like keep shorter definitions with declarations, but keep larger definitions at the end of file?

[halx99]

I prefer first one, less code