Make the infinity case nicer.
correct handling of Math.gamma(+/-0.0)
add INFINITY, NAN, infinite?, nan? to Float
untag newly working tests.

one still fails because rlib's gamma function is less precise for
gamma(23) (and probably nothing else).
infinite? returns the sign of the infinity
Fix Float.nan (maybe I should read docs?)
rename and fix test_nan
Merge branch 'master' of https://github.com/topazproject/topaz

Conflicts:
	spec/tags/core/math/gamma_tags.txt
	tests/modules/test_math.py
	topaz/modules/math.py
write the test with the proper constants

now that we have them
Merge 44526603b2ab388fceb99de625f3282c4a2a8d99 into cdbe5377c4394a7f9243cbc1a372e5126e60dbc5
Merge branch 'master' into gamma-improvements

Conflicts:
	spec/tags/core/math/gamma_tags.txt
float("inf") is not RPython
skip for travis
Merge branch 'master' of https://github.com/topazproject/topaz