Declaration of new functions
Merge branch 'master' of https://github.com/jeremyletang/rgtk
New widgets: Dialog and AboutDialog
Merge branch 'master' of https://github.com/jeremyletang/rgtk

Conflicts:
	gtk_glue/gtk_glue.c
	src/gtk/ffi.rs
	src/utils/cast.rs
New widgets : Dialog and AboutDialog
New widget : ColorChooserDialog
New trait : ColorChooser
Delete unused macros and converted Gboolean params in bool
Deleted some useless changes like double reimport or public export
Merge pull request #16 from GuillaumeGomez/master

New widget : ColorChooserDialog
New widget : MessageDialog
Merge pull request #17 from GuillaumeGomez/master

New widget : MessageDialog
begin work on glibs list types
add List, more trait impls on List + SList
remove warning from test file
Merge pull request #18 from jeremyletang/glib-lists

Glib lists
Suggestion: When foreign functions are nearly sure to return proper values
dont wrap in an Option monad but just fail if the foreign function returns
invalid data.

I think it is OK to `fail!` instead of option when there is really an error
state.