Flarum 1.0 compatibility

• Add compatibility with Flarum 1.0
• Make available on the admin frontend as well
• Allow inspecting lib translations
• Allow inspecting translations defined in flarum/core
• Add global startTranslationInspection() function to start inspector even when button is inaccessible
• Link to exact tag on GitHub instead of master branch
• Hide inspect button from frontend if user doesn't have permission to inspect