Added required assemblies, sparklrText changes

- Tried a different approach for #33.
- Added workaround for #40, still needs "real" fixing.
Synchronized post list, added usernames to main

- Synchronized post list with dispatching (could solve #34)
- The post list is now sorted by the last modification date (closes #43)
- Added names to main page (closes #19)
- More work on the post, closes #33 again
Made login asynchronous

- Changed Client.Login to LoginAsync, is awaitable
- Might have broken the support with the PCL, however async is supported
on Windows 8 (RT), Windows Phone 7 and Windows Phone 8
- see #42 for discussion
json requests are now async

- Commit to save the state, needs more work
see #42 for discussion
Made posting async

- see #42 for discussion
Finished making the calls async

- Made the remaining functions async (see #42)
Manual merge
Manual merge again, hopefully right