Add floating point primitives to LLVM codegen
Add declaration for __gmpz_get_d and kill some parens
Fix LIntFloat in LLVM backend
Fix LIntFloat in LLVM backend
Fix LLVM Code generation for float primitives yet again

- Was using the wrong opcodes (Add, Sub, Mul, SDiv) for arithmetic operations
  now uses FAdd, FSub, FMul, FDiv
- Don't attempt to sign extend floats
The result of a comparison is not a float!
Adjust format string for casts from float to string
Move some floating point stuff out of the way
Implement remaining floating point primitive functions
Revert "Move some floating point stuff out of the way"

This reverts commit b3bc27787cd9d1bba65a7347ae5d857ed61c735a.
LLVM Codegen: some refactoring

- subsume fbin and ibin in one function binary
- subsume fUn and iUn in functions unary and nunary (name unary)