Changed url's encryption from base64 to md5

Fixes Issue #243.
md5 hashes are only coded on 32 hexadecimal characters, so it won't make
too long file names.
Changed Flattr Caching System

From md5(url) to the ID of an article. Easier and faster.
Merge branch 'dev' of git://github.com/tcitworld/poche into tcitworld-dev
remove print_r