[Vala] Bunch of compilation warnings in a Vala GTK3 app

[Satyajit Sahoo <satyajit happy gmail com>]

I'm writing a simple GUI with GTK3 and Vala. It compiles and works fine.
But gives me a bunch of errors while compiling,

The code is here
https://dl.dropbox.com/u/8501878/gnome-shell-theme-elegance-colors.zip

I'm on Ubuntu and using Vala 0.18 from Vala PPA.

valac --pkg gtk+-3.0 elegance-colors-gui.vala -o elegance-colors-gui
/home/satya/Workspace/gnome-shell-theme-elegance-colors/elegance-colors-gui.vala.c:
In function ‘elegance_colors_window_export_theme’:
/home/satya/Workspace/gnome-shell-theme-elegance-colors/elegance-colors-gui.vala.c:441:10:
warning: assignment from incompatible pointer type [enabled by default]
/home/satya/Workspace/gnome-shell-theme-elegance-colors/elegance-colors-gui.vala.c:483:11:
warning: assignment from incompatible pointer type [enabled by default]
/home/satya/Workspace/gnome-shell-theme-elegance-colors/elegance-colors-gui.vala.c:
In function ‘elegance_colors_window_on_export’:
/home/satya/Workspace/gnome-shell-theme-elegance-colors/elegance-colors-gui.vala.c:612:11:
warning: assignment from incompatible pointer type [enabled by default]
/home/satya/Workspace/gnome-shell-theme-elegance-colors/elegance-colors-gui.vala.c:658:11:
warning: assignment from incompatible pointer type [enabled by default]

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Satyajit Sahoo
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