remove the cmath module, and remove the redundant layer of wrapper functions

[thestinger]

Rust should expose the full standard C99 math library through the Float trait. The cmath module will then be an implementation detail we don't need to expose. This will allow Rust to move to a specific math library in the future too rather than using the standard C library provided by the OS.

At the moment, a macro is used to generate a whole bunch of wrappers around these functions. This actually makes the code longer, rather than shorter, so I don't see a point in keeping it around.

[ngsankha]

Hasn't this been done already?

[thestinger]

No, it's not done. The extra layer of wrappers is still there in the f32 and f64 modules and the cmath module also still exists.

[thestinger]

The cmath module is now removed, but the duplicate free functions acting as wrappers still need to go.

[pongad]

Working on it

[thestinger]

@pongad: By the way, I think some of these aren't yet exposed as methods on Float at all and they should be.

[pongad]

@thestinger I just found that out too. Will take care of it after today's exams are over :D