Teal 13 17 acu134044 support mingw

@szmyd changed right_develop's Shell definition from module to singleton class similar to right_git change due to difference in behavior between ruby 1.8 and 1.9
fixed issue with some utility/git methods calling .map on a string instead of .lines.map which doesn't work in ruby 1.9
fixed combination of clean_bundler_env and :set_env_vars option of shell.execute due to clean bundler env wiping out the env vars set by option