Clean up & readying for release

Bugfixes:
- make sure wp-ajax-response is always loaded
- make sure spinner will show whether row actions show or not
- Solidified & tested error codes in ajax js
- escaping of '_' in sql query
- reflection didn't always return something
- quoting of phrases for google search urls

Enhancements:
- add "view online" link to row actions after details retrieval
- added title tag to images
- display of doc comment info

Other:
- General clean-up, documentation update and removal of debug code
- Updated minified files
- Added screenshots
- Added banner
- Updated .pot file and added partial Dutch translation