a liitle caja improvment in gtkrc files and remove of some deprecations in gtk-3 themes

1. the caja improvement fix a theme issue with my caja-terminal.
before in ie. Aldabra
https://dl.dropbox.com/u/49862637/Mate-desktop/Bugs/caja-aldabra.png
after
https://dl.dropbox.com/u/49862637/Mate-desktop/Bugs/caja-aldabra2.png

2. fix "Not using units is deprecated. Assuming 'px' " in gtk3 themes.

Hope that's better now.