Introduce Robospice to better handle async task.

For now, only conversation details is retrieved via Robospice.
Introduce Robospice to better handle async task.

Now, Timeline can also be retrieve via Robospice framework.
Link Robospice calls to Activity lifecycle instead of fragment one.

As a consequence, same pattern is used for both timeline and details.
All request are handle by robospice framework.

 - SyncAdapter now use robospice implementation
 - OnPullToRefresh use TimelineActivity spiceManager
TimelineActivity handles now PullUpToRefresh AND PullDownToRefresh
pattern.
Merge pull request #6 from pariviere/feature-robospice

Introduce Robospice framework