Altitude Adjusted FTP

This is an early version of my datafield that displays the user's FTP corrected for altitude using the formula derived by Alex Simmons (http://alex-cycle.blogspot.de/2014/12/wm2-altitude-and-hour-record-part-ii.html). The user FTP must be set using the Connect app or Garmin Express. The datafield then uses the current altitude to display the altitude-adjusted FTP. Current limitations * The given FTP is assumed to correspond to sea level. If you have estimated your FTP at a higher altitude, the datafield will show a lower value at that altitude, since it assumes the FTP to be valid only at sea level. A future version will allow to correct for this.

v0.3: support for altitude-acclimatized athletes added (using formula by Bassett et al, valid after several weeks at altitude) v0.2: improved formatting (rounding to full integers) v0.1: initial release