default to no color when terminal is dumb
default to no color when terminal is dumb

Signed-off-by: Wagner Riffel <4a7f7a077567e5c044aebfccebb8b6db3bb33fc5@gmail.com>

JFLarvoire/the_silver_searcher,ggreer/the_silver_searcher,JFLarvoire/the_silver_searcher,JFLarvoire/the_silver_searcher,JFLarvoire/the_silver_searcher,lizh06/the_silver_searcher,JFLarvoire/the_silver_searcher,ggreer/the_silver_searcher,ggreer/the_silver_searcher,lizh06/the_silver_searcher,lizh06/the_silver_searcher,ggreer/the_silver_searcher,lizh06/the_silver_searcher,JFLarvoire/the_silver_searcher,JFLarvoire/the_silver_searcher