BiBer API added (#33, #116)

Combination of many commits:

First introduction for BiBer1992 with 1 library: Offenburg
Supports Mediatype choice for search, no branches, no accounts yet

BiBer1992
Added NRW/Essen, NRW/Hagen, Bay/Würzburg, BaWü/Friedrichshafen
Added support for branches

Added: Bay/Aschaffenburg

added: NRW/Gelsenkirchen

added: NRW/Herford, NRW/Lünen, NRW/Duisburg

MIT license in BiBer1992.java
getResults() implemented
getShareUrl() implemented

BiBer1992: Support for addCopy() "Exemplare" for the Libraries which
have the right table layout:
 * BaWü/Friedrichshafen
 * Bay/Würzburg
 * NRW/Duisburg
 * NRW/Gelsenkirchen
 * NRW/Hagen
 * NRW/Herford

BiBer1992: Account support (Konto) for BaWü/Offenburg
Account and prolong single media.

Don't display "copies" headline without data (#120)
About dialog made ready for multiple authors
Fix Both loading indicators displayed (#121)
Deleted duplicate library file
Organize bookmarks through a ContentProvider
Solving #96 on the way
Fix IllegalStateException on connection retry (#118)
New icon set used (#103)
Bond26: Fix reservations in Heidelberg
OCLC2011: Blind fix for Hürth (#29)
Prepare for release