Add filter_type optative parameter to objectchooser
Add filter_type optative parameter to objectchooser

Constants are defined to select the different filter_type
values. A comment was added to document the use.

Signed-off-by: Gonzalo Odiard <8e43bec6c9a4aba7dc358247a21ab52d301a2840@laptop.org>

puneetgkaur/sugar-toolkit-gtk3,quozl/sugar-toolkit-gtk3,i5o/sugar-toolkit-gtk3,Daksh/sugar-toolkit-gtk3,manuq/sugar-toolkit-gtk3,Daksh/sugar-toolkit-gtk3,i5o/sugar-toolkit-gtk3,manuq/sugar-toolkit-gtk3,tchx84/sugar-toolkit-gtk3,quozl/sugar-toolkit-gtk3,puneetgkaur/sugar-toolkit-gtk3,tchx84/debian-pkg-sugar-toolkit-gtk3,sugarlabs/sugar-toolkit-gtk3,tchx84/sugar-toolkit-gtk3,i5o/sugar-toolkit-gtk3,samdroid-apps/sugar-toolkit-gtk3,samdroid-apps/sugar-toolkit-gtk3,samdroid-apps/sugar-toolkit-gtk3,sugarlabs/sugar-toolkit-gtk3,Daksh/sugar-toolkit-gtk3,godiard/sugar-toolkit-gtk3,quozl/sugar-toolkit-gtk3,godiard/sugar-toolkit-gtk3,sugarlabs/sugar-toolkit-gtk3,puneetgkaur/sugar-toolkit-gtk3,quozl/sugar-toolkit-gtk3,puneetgkaur/backup_sugar_sugartoolkit,puneetgkaur/backup_sugar_sugartoolkit,i5o/sugar-toolkit-gtk3,godiard/sugar-toolkit-gtk3,tchx84/debian-pkg-sugar-toolkit-gtk3,samdroid-apps/sugar-toolkit-gtk3,manuq/sugar-toolkit-gtk3,puneetgkaur/backup_sugar_sugartoolkit,tchx84/debian-pkg-sugar-toolkit-gtk3,tchx84/sugar-toolkit-gtk3