Support uploading/downloading patches

[mfojtik]

The record can possibly upload the patches to Tracker application where they will be stored in database. Later on when reviewer want to apply them, he don't need to manually save emails with patches but rather just call tracker apply ID and the patchset ID will be downloaded and applied in current working branch.

[mfojtik]

This is done by:

$ tracker record -u

or

$ tracker upload

Patches can be downloaded then using:

$ tracker apply COMMIT

or

$ tracker download SET_ID