type process_data_t. This was an artifact when the choice was
made to use the void * type for the data parameter in processes.
Changed parameter 'void * data' of process_post_synch to
process_data_t for consistency.
Checked all the uses of process_start() in contiki and fixed casts
of the data parameter.
Twitter removed http basic auth from the api in august 2010, but this
underlying code is a good example of doing http basic auth in contiki.
The app has been renamed, and some fixes applied to make it build
cleanly.