Changes to improve GPS/sensor polling, linear regression math, and glide ratio calculation

* GPS updates now use single update for better control over update
frequency (requires API 9)
* Fixed several cases where update MS is treated as second values
* Wiped out LocationUtils distance calculation in favor of Android OS
one (old one seemed incorrect, and produced huge numbers for glide
ratio)
* Upped bariometric sensor polling frequency (gives linearregression
more samples)
* Test GPS writer now attempts to read the test file in correct timing
* Updated linear regression math to reduce number magnitude mismatch and
multiplication of raw timestamps
Reverted GPSClient polling change.

* using single updates was causing too many issues with GPS wakeup &
etc.
resetting linear regression on altitude reset

fixes vertical speed jump after location fix (annoying bleeps)
Added google elevation support to GPSClient

Better altitude correction through Google Elevation.
UI support for displaying the current altitude calibration

* added calibration display to altitude info.
fix livetrack24 server url
removed unused files