Created tags GAE service.
Added model and dao classes.
Implemented servlet & label assignment.
Fixed NPE on empty parameters.
Implemented label querying request.
Reorganized folders.
Merge branch 'issue-16' into develop
Implemented an activity switcher dialog.
Added placeholders for tags activity.
Launcher now properly closes on back key.
Added Apache HTTP utils library.
Implemented tags client requests.
Removed unused imports.
Fixed parsing of HTTP response.
Added visual indicators for operations.
Removed unused methods.
Fixed cloud-demo project properties.
Fixed NPE on empty tag.
Reformated legacy code.
Added missing file.