Merge pull request #725 from Ivoz/more-gitignore

Add .tox to gitignore

.gitignore

-*.py[co]
+*.py[cod]
 build/
-*.so
-*.pyd
 .runtimes
+.tox/
+*.so
+*.egg-info
 gevent.*.[ch]
 gevent/corecext.pyx
 gevent/__pycache__
 gevent/libev
 gevent/_corecffi.c
 gevent/_corecffi.o
-*.egg-info
 Makefile.ext
 MANIFEST
 *_flymake.py