Update: GWTP, GWT and various libraries updated. Closes #27 and #33

GWTP updated to 1.2.1
GWT updated to 2.6
GIN updated to 2.1.2
gquery updated to 1.4.1
jukito updated to 1.4
guava updated to 16.0.1
Update: Fix moved classes from client to shared #33

Some classes were moved from client to shared. Replace them in the source files
https://github.com/ArcBees/GWTP/wiki/Migrating-from-1.1-to-1.2
Bugfix: Remove unecessary workaround for GWT bug #27
Update #27: Switch target version from Java 6 to Java7

GWT 2.6 supports Java 7.
Merge branch 'GWTP_GWT_update'