This patch increments the DVB-API to version 5.1 in order to reflect the addition of ISDB-T and ISDB-Tsb on Linux' DVB-API.

Changes in detail:
- added a small document to describe how to use the API to tune to an ISDB-T or ISDB-Tsb channel
- added necessary fields to dtv_frontend_cache
- added a smarter clear-cache function which resets all fields of the dtv_frontend_cache
- added a TRANSMISSION_MODE_4K to fe_transmit_mode_t

Signed-off-by: Olivier Grenie <olgrenie@dibcom.fr>
Signed-off-by: Patrick Boettcher <pboettcher@dibcom.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

This allows application developers to query the dvb-core API version
dynamically, helping developers understand whether certain features
will be available.

Signed-off-by: Steven Toth <stoth@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

The cx23415 adds some extra features that this DVB decoding API did
not support. This API has been expanded to support the required
features. Both source and binary backwards compatibility is kept
intact by these changes. So existing applications are not affected.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Ralph Metzler <rjkm@metzlerbros.de>
Signed-off-by: Oliver Endriss <o.endriss@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!