Implemented IEquatable<T> to speed up equality comparisons.

Actor, CPos, CVec, WAngle, WPos, WRange, WRot and WVec structs now implement IEquatable<T> which means unboxing/casting costs can be eliminated.

Also simplified the ToString method by concatenating components directly rather than using a format string since the overhead is a bit high for simple cases like this.
Also implemented on the Bits<T> struct.
Merge pull request #5400 from RoosterDragon/equatable

Implemented IEquatable<T>