* removed old swing JEditorPane based html to png rendering due to
it's lack of support for modern css
* new implementation uses wkhtmltoimage (on prod server via wrapper
script using xvfb)
* no longer generating image on every GET request for QR, but rather
generating image when a bounty is cretaed or contract balance
changes
* images stored to DB
* comment image design updated according to UI spec
Teemu Patja
kagel
Adrian Tiberius