big: Add get(a, type) and get_float.

core/math/big/common.odin

@@ -35,13 +35,6 @@ _DEFAULT_SQR_KARATSUBA_CUTOFF :: 120;
 _DEFAULT_MUL_TOOM_CUTOFF      :: 350;
 _DEFAULT_SQR_TOOM_CUTOFF      :: 400;
 
-/*
-	TODO(Jeroen): Decide whether to turn `Sign` into `Flags :: bit_set{Flag; u8}`.
-	This would hold the sign and float class, as appropriate, and would allow us
-	to set an `Int` to +/- Inf, or NaN.
-
-	The operations would need to be updated to propagate these as expected.
-*/
 Sign :: enum u8 {
 	Zero_or_Positive = 0,
 	Negative         = 1,