fix compile errors with gcc 4.1.x and 4.2.x

 - tested with gcc 4.1.2, 4.2.1, 4.4.6, 4.6.3 and 4.7.2
 - disable gcc ignore pragma for "-Warray-bounds" if gcc version < 4.3
   - when I took out the pragma tvheadend compiled fine in all the above compilers, but I assume some version of gcc is issuing a false-positive.
   - "-Warray-bounds" was added in gcc 4.3: http://gcc.gnu.org/gcc-4.3/changes.html
 - fixes typo in cmdline help for -C
 - clarify usage of -a in help description
timeshift: minor addition to atomics (check max size correctly).
tvhtime: start adding time processing support to TVH
Fix #1608 - atomic: add workaround for missing intrinsic atomic ops.
dvb: some minor corrections to nit scanning.
Fix #1605 - timeshift: mark file space as free at earliest opportunity.

Previously the space was only marked as free when the file was physically
removed (which happens async) which resulted in the buffer immediately
being seen as full.
Merge remote-tracking branch 'origin/pr/242'
Cosmetics: epg genre
atomic: fix previous merge mistake
comsetics: some updates to --help output.

Changes are based on suggestions from Vuolter <vuolter@gmail.com>
webui: break configuration into multiple super tabs

This is done to limit the total number of tabs on one row which is
leading to problems on smaller displays. I also think its more
logical.