Added util File

Added a util file to contain functions used in multiple backend files
Backend Bugfix

getFilteredEntries now really works with ids and textversions of tags and types
Backend Bugfix

removeTag now really works with ids and textversions of tags and types
Backend Bugfix

Checking for ints and converting them in getTag
Extended Backend

Added addTag.php closes #26
AUTHKEYS EVERYWHERE

Added check for authkey in all backend files, even if the key is not necessary closes #29
Backend Bugfix

Login now with email and not username fixes #22
Extended Backend

Added updateImage closes #5
Extended Backend

Added updateType closes #28
Merge branch 'master' of https://github.com/CrazyCrud/shithouse_poetry