Beginning of GValue
GValue : work in progress
Compilation OK
Update to last rust compiler version
GValue are now working, see treeview example
Making better GValue use, still in progress
Still in progress
End of GValue implementation
Add get example
Add GType "widget"
Merge pull request #123 from GuillaumeGomez/master

add gvalue + support for treestore
fix Widget trait implementation
This trait was implemented for a lot of struct who was not widgets
this fix this by removing the implementation for the given struct and fixing
the resulting problems.
fix travis build
begin implementation of safe signals
add impl_*_event macros, for implements invents
for the moment only events for widget and existing events are binded.