Animate GIF support restored.

Fixes #525
Revised .htaccess that works better on shared hosts
Preventing transparent PNGs from being clobbered
Do some sanitisation on some configuration provided data (refs #518 and various others)
Merge pull request #533 from mapkyca/ini-sanitisation

Do some sanitisation on user supplied configuration settings
Fixing URL over sanitization in profile fields
Removed confusing syndication clause

Fixes #535