closesTryGhost/Support#426
refs TryGhost/gscan#106
needs TryGhost/gscan#107
GScan can return errors, which was not handled in our theme validator and caused Ghost to crash completely. GScan will now return an Ignition error when its not able to read the `.zip` file.
e. g.: `{"errors":[{"message":"Failed to read zip file","context":"tife.zip","errorType":"ValidationError","errorDetails":"invalid relative path: ../tife/"}]}`
no issue
- discovered while testing
- activate theme
- download theme
- modify theme
- upload theme
- override? yes
- translation files are not reloaded, because the database is up-to-date
- remove un-used events in theme api layer
- trigger event from theme service
