Update de.po

"Behörde" wurde zu "Institution" wenn es sich nicht um administrative Einrichtungen handelt.

"Antrag" wurde zu "Anfrage" oder "Registrierung", weil webtrees keine Behörde ist (einen Antrag stellt man in Deutschland nur bei Behörden, alles andere sind Anfragen).
Added missing translation, some fixes
Merge pull request #144 from Art4/patch-1

Added missing translation, some fixes
CSS typo
Undefined variables error in import wizard
Refactor global user functions into new User/Auth classes
Hard-coded table prefix
Remove unused code
Conflict in variable names
Error handling logic in login.php
Create separate route for logout
New User class breaks changes log #145
Consistently use WT_ROOT in the require/require_once statements (where missing)
Merge pull request #146 from jon48/hotfix/proposal

Consistently use WT_ROOT in the require/require_once statements
Cleanup - unused code
Cleanup - unused code
Cleanup - unused code
Interactive tree - show all spouses option fails when chart is embedded in home page
Cleanup - parameters incompatible with declarations
Cleanup - unused code