Merge pull request #8 from mathijshenquet/master

Various changes
Merge pull request #9 from mathijshenquet/master

Signals, GDK and refactoring
fix build on osx
- update Makefile to build gtk_glue as static on osx
- restore some metadata on rgtk.rs, these are not used by cargo but still usefule for rustc
- add the test program as a target for cargo
Merge pull request #11 from mathijshenquet/master

Refactoring
implements drops to all widgets
rename Widget::wrap_widget() -> Widget::wrap()
Merge pull request #12 from jeremyletang/impl-drop

implements drops to all widgets
Merge pull request #13 from jeremyletang/widget-renaming

rename Widget::wrap_widget() -> Widget::wrap()