Faster wireframe gen

[slimbuck]

Use Set to track line hashes and use plain math instead of bit math. Also correctly support meshes with more than 65535 vertices.

This change results in roughly double the speed generation of indices.

[LeXXik]

I am curious to read about the info that led you to swap out bitwise operations.

[slimbuck]

w3 schools says:

JavaScript Uses 32 bits Bitwise Operands

JavaScript stores numbers as 64 bits floating point numbers, but all bitwise operations are performed on 32 bits binary numbers.

Before a bitwise operation is performed, JavaScript converts numbers to 32 bits signed integers.

After the bitwise operation is performed, the result is converted back to 64 bits JavaScript numbers.

[slimbuck]

@LeXXik, using set makes a bigger difference than bit operations for performance. I kept the vanilla math over bit operations so it'd work correctly for meshes with more than 65536 vertices.