Moblin UI framework .desktop file support is not standard compliant

Problem Description: Merging with bug 249206. The moblin UI framework does not use the .desktop files in /usr/share/applications the way it should according to freedesktop.org and moblin.org standards. Here is a summary of the main problems:

1. When the Categories field of a .desktop file contains multiple categories, the application does not appear in multiple places on the menu/desktop. (See http://standards.freedesktop.org/menu-spec/latest/ar01s03.html).
2. Spaces are valid in .desktop file values, but they are not handled correctly in either the EXEC or ICON fields. See http://standards.freedesktop.org/desktop-entry-spec/latest/ar01s03.html.
3. Full paths need to be supported in both the EXEC and ICON fields. http://standards.freedesktop.org/desktop-entry-spec/latest/ar01s06.html

Applications that have desktop files that have full paths (with or without spaces) in the ICON and EXEC fields neither show up in the menu correctly nor launch correctly.

Steps to Reproduce #1:
1. Edit /usr/share/applications/pidgin.desktop
2. Change Categories=Application;Network; to Categories=GTK;Application;Network;Utility;
3. Restart GDM
4. Select "Internet" Category menu filter
5. Select "Accessories" Category menu filter
6. Edit /usr/share/applications/pidgin.desktop
7. Change Categories=GTK;Application;Network;Utility; to Categories=GTK;Application;Utility;Network;
8. Restart GDM
9. Select "Internet" Category menu filter
10. Select "Accessories" Category menu filter

Actual Result:
Icon/Launcher only appears in the "Internet" submenu when Network appears first in list, and only appears in "Accessories" submenu when Utility appears in list first.

Expected Result:
Icon/Launcher appears in both Utility and Network submenus.
Application launches. See http://standards.freedesktop.org/desktop-entry-spec/latest/ar01s03.html for valid .desktop file values. Values of type string may contain spaces.

Any Workarounds:None

Steps to reproduce #2 and #3 using pidgin:
1. $>mkdir -p /home/ume/test\ folder\ with\ spaces/
2. $>cd /home/ume/test\ folder\ with\ spaces
3. $>sudo ln -s /usr/bin/pidgin .
4. Edit /usr/share/applications/pidgin.desktop
2. Change EXEC=pidgin to EXEC=/home/ume/test\ folder\ with\ spaces or EXEC="/home/ume/test folder with spaces"
3. Restart Crown Beach Device
4. Click on Pidgin icon

Actual Result:
Application fails to launch.

Expected Result:
Application launches. See http://standards.freedesktop.org/desktop-entry-spec/latest/ar01s03.html for valid .desktop values. Values of type string may contain spaces.

Any Workarounds:
Create a symbolic link in a path that does not have spaces, and point the EXEC field to that link.