[f32] Add conversion routines.

[Zeda]

Higher priority

• [x] ~~f32toa - Convert an f32 float to a string to be displayed.~~
  • ~~Currently this is emulated by converting the f32 to a "single" and then using singletostr to convert to a string. This means that the f32 library requires mulSingle and the single constants instead of using the already available f32mul and f32 constants.~~
• [x] ~~atof32 - convert a string to an f32 float.~~

Integer conversions

• [x] ~~f32toi8~~
• [x] ~~i8tof32~~
• [x] ~~f32toi16~~
• [x] ~~i16tof32~~
• [x] ~~f32tou8~~
• [x] ~~u8tof32~~
• [x] ~~f32tou16~~
• [x] ~~u16tof32~~

Conversions between floats

• [x] ~~f32tosingle~~
• [x] ~~singletof32~~
• [x] ~~f32tof24~~
• [x] ~~f24tof32~~
• [x] ~~f32tof16~~
• [x] ~~f16tof32~~
• [x] ~~f32tox~~
• [x] ~~xtof32~~
• [x] ~~f32tof64~~
• [x] ~~f64tof32~~
• [ ] f32toTIFloat
• [ ] TIFloattof32