- Also display inheriting template on style installation (previously, it was only displayed on template installs)
- Fixes undefined variable in error message if inheriting style does not work
- Fixes export of styles/templates and correctly set inherit_from variable
git-svn-id: file:///svn/phpbb/branches/phpBB-3_0_0@8943 89ea8834-ac86-4346-8a33-228a782c2dd0