add filebrowser urls
Add dummy FileBrowseField

This is needed since Mezzanine imports it from PACKAGE_NAME_FILEBROWSER, which
should be mezzanine_grappelli.filebrowser for compatibility with the urls
import.
add padding in breadcrumbs box
override default TinyMCE config to look more like Grappelli
Remove 'Search & replace' button in TinyMCE

Since Grappelli doesn't have any icon for it.
fix actionlist icons
fix delete icon on pages list page
fix filebrowser when using frontend editing
fix TinyMCE style to make it more visible
fix breadcrumbs menu background color to match Grappelli's one
make Mezzanine collapse classes work with Grappelli