Add page speed+altitude + Refactor

UI seems ok, but tests need to be done!
Send altitude
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
Topbar + altitude fields with 4 characters
Improve topbar

* display topbar on speed page
* time tick refreshs topbar
Imperial units for altitude fields
v1.2.0-beta2
Bugfix: speed length without dot

+ bugfix if speed is sent with comma instead of dots (older app sent localized numbers)
v1.2.0-beta3
v1.2.0
Merge pull request #1 from jay3/master

Version 1.2.0