Merge pull request #2 from Ogeon/master

Fix support for multiple objects
Fix grouping if usemtl comes before the first face.
Merge pull request #3 from csherratt/fix_grouping

Fix grouping if usemtl comes before the first face.
remove debug as it was not used
Merge pull request #4 from csherratt/no-debug

remove debug as it was not used
fail! -> panic!
fix warnings
fix nameing for HashMap
update to latest rustc
rename obj-rs to obj
update Cargo.toml for package
update travis.yml
Wrap Words iterator in a ByRef in to_string