Improve readme, ditch features, don't impl Float

Cargo.toml

@@ -13,25 +13,9 @@ bench = false
 name = "operations"
 harness = false
 
-[[bench]]
-name = "math"
-harness = false
-
 [features]
 default = ["num-traits"]
 
-# disable-able fast-math features
-no-finite-math-only = []
-no-associative-math = []
-no-reciprocal-math = []
-signed-zeros = []
-trapping-math = []
-fp-contract-on = []
-no-approx-func = []
-math-errno = []
-
-# TODO denormal-fp-math? can have cpu-wide consequences
-
 # optional trait implementations
 nalgebra-v021 = ["num-traits", "nalgebra_v021", "simba_v01", "approx_v03"]
 nalgebra-v029 = ["num-traits", "nalgebra_v029", "simba_v06", "approx_v05"]