fix some problems with missing config file

Probably wouldn't happen, but if you do delete the config file with the
setup scripts protected you can now recover and run setup.
Allow 3rd party themes to set the "distributed" value

So you can "claim" that your theme is free of deprecated functions (see
#27). Set $theme_description['distribution'] = 'xxxx'; where xxxx is
anything but "ZenPhoto20" and the theme will be locked to editing and
will not cause the deprecated functions plugin to be enabled.
bypass for themes on deprecated functions enable
fix #29
Merge pull request #30 from sbillard/master

fix #29