epgcache: advise epg.dat POSIX_FADV_DONTNEED after reading

epg.dat can take up quite a bit of page cache, which we
will never use again (epg.dat is just a temporary file,
and will be overwritten with new data)
eDVBTSRecorder: increase demux buffer size to 1MB

The (in-kernel) demux ringbuffer does not need to be
packet aligned, we can pick any size.

And even though our userspace buffers are quite large,
we need a reasonable kernel buffer to cope with fluctuations
in the rate at which userspace is able to read (and handle)
the demux data.
add pgettext support
Revert "EventName: Make Now Next better translatable"

This reverts commit 1eb7e9f6ed955a3e7fdb8e50baa0333a16a2fa3f.
Revert "NextEpgInfo: Fix a typo"

This reverts commit 6666f41676f1de0ca9906a82c0a77ecddff867e2.
Revert "NextEpgInfo: See the previous commit - for translations"

This reverts commit c912b9bd1560c620a9cb11162576ceb79d46d416.
use pgettext for ambiguous translations

allowing different translation for different contexts
po file update

with new message contexts
update cs.po

Signed-off-by: pieterg <pieterg@users.sourceforge.net>
german translation updates by Frogman
eDVBTextEncodingHandler: use /etc/enigma2/encoding.conf when available

allowing a personal encoding.conf, which will not be subject to
system updates
configure.ac: set DREAMBOX define on Dreambox hardware
hdmi_cec: add dreambox support
configure.ac: fix DREAMBOX conditionals
InfoBarGenerics: Prevent GS when preferred recording path is None
dvb: fix compiler warnings
configure.ac: restructure DREAMBOX conditionals
eGTable: allow number of retries to be overridden
UsageConfig: Instantly change Channellist when setup of it is changed
Introduce alternative numbering mode

The alternative numbering mode that can be choosen in the User Interface
settings arranged that every userbouquet does start with service number 1.
By default it is off as the service numbering is not uniq anymore.
It can be used when you want to have the original provider numbering when
it is not at the first userbouquet.