Add page speed+altitude + Refactor

UI seems ok, but tests need to be done!
Send altitude
fixed bug with units display

Signed-off-by: Nicholas Jackson <nic@thatlondon.com>
Add accuracy field
Initial values
Buffer size + debug sync_error_callback
Merge remote-tracking branch 'github/master' into dev_page_altitude

Conflicts:
	pebblebike/src/pebblebike.c
v1.2.0-beta1