allow theme of fileselector_entry components.

allow theme of fileselector_entry components.

Right now I'm abusing style, setting fileselector_entry/$style on
items, however if it's not found the fallback will be 'default' and
not 'fileselector_entry/default' as it should be.

I'm wondering if this should be implemented in elm_theme.c by
replacing the last '/$component' with '/default', the remove it and
try again, like:

{{{
        input = a/b/c
        pass1 = a/b/default
        pass2 = a/b
        pass3 = a/default
        pass4 = a
        pass5 = default
}}}

SVN revision: 53423