pythonconsole: Remove deprecated function

Use GdkRGBA instead of GdkColor.

https://bugzilla.gnome.org/show_bug.cgi?id=739648
pythonconsole: Remove GtkDialog

Used GtkGrid directly instead of GtkDialog.
Removed deprecated properties of GtkColorButton.

https://bugzilla.gnome.org/show_bug.cgi?id=739648