le: timeout after 5 seconds of no packets on a data channel

This is very ugly code that should be cleaned up.
Remove outdated build instructions
Merge branch 'master' of https://github.com/greatscottgadgets/ubertooth
Latest release is R2.. right?

Updating README to reflect latest version available.
Merge pull request #27 from EMCP/patch-1

Latest release is R2.. right?
le: test for transfer doneness based on DMA registers

This works around an issue in which the firmware was hanging partly due
to rx_tc not being incremented under certain circumstances. With my
limited testing, this fixes #15.
Merge remote-tracking branch 'upstream/master'