Add --disable-avahi configure option, and make pidvbip compile when avahi is disabled or missing
New configure/build system

The configure.inc script and much of the layout of the other files
has been borrowed from tvheadend
fix erroneous #if that occured during merge conflict resolution
Merge pull request #11 from adamsutton/feature/new-build-system

New configure/build system
Add proper command-line parsing, and unify with the config file parsing.  We now only have a single config file location (~/.pidvbip) which can be overridden with the command-line.  Use pidvbip --help for the full list of options (some have been renamed).
Fix displayed path for pidvbip binary to match Makefile
Some configfile cleanups.
Add CEC channel-list key mapping
Add --no-cec option to disable CEC support
Fix the description of startup-stopped
Add checks for libavcodec and libavutil, as they are also needed
Remove bash-ism from clean: rule
Fix AVAHI after configfile changes
Merge to master