Implementing "-n" flag

plus its prerequisite `Kernel.gets`
Implementing `Kernel.gets` loop in RPython and moving it to the right spot
Changes per feedback
Trying out a pre-built frame version of Kernel.gets loop
Merge remote-tracking branch 'upstream/master' into mbh/dash-n-flag-plus-Kernel#gets
implement Math.gamma
Merge branch 'master' of https://github.com/topazproject/topaz

Conflicts:
	topaz/objspace.py
add myself to AUTHORS.rst
Make the infinity case nicer.
correct handling of Math.gamma(+/-0.0)
Fixed #488 -- added a link to the rubyspec and mspec repositories
Merge pull request #480 from modcloth/mbh/dash-n-flag-plus-Kernel#gets

Implementing "-n" flag
Merge pull request #487 from cfbolz/master

Add Math.gamma
updated specs for gamma
cleanup, put this exception in the math module
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