Add track functions
Merge remote-tracking branch 'origin/master' into tracks
loadTraсks method
loadTrack method
Create track method
deleteTrack method
Update tracks API
Fix bugs in createTrack method
createTrack method doc
Load tracks method doc
Document track methods
Merge branch 'master' of github.com:oss-fruct-org/gets into tracks
Merge branch 'tracks' into master