Preparatory Makefile cleanups for packaging.

Use CPPFLAGS if specified (Debian uses CPPFLAGS to provide some hardening defines)
Use DESTDIR if specified (packaging systems use this to install to a temporary location when building)

Merge all the duplicated makefiles into one that builds all the binaries.
Stub out the old makefiles to delegate to the main one for the sake of people building with old instructions.
Support $(DESTDIR) for manpage installation.
Don't compress the manpage, that's usually done in a packaging step.
Copy debian controlfiles from dump1090_builder.

This is just a blind copy with no modifications to give a clear starting point; it will not build yet.
Consistently call this "fadump1090" everywhere to disambiguate it from any other dump1090.
Build on any architecture, not just armhf.
Fix a description typo.
Add Build-Depends: librtlsdr-dev

Raspian does not include this package by default, however it is available in wheezy-backports
(or we could build and distribute our own version if needed)
Remove the DESTDIR and auto_install overrides.

With the updates to the Makefile, the debhelper defaults work fine here.
Add debian/compat, debian/source/format to fix a couple of lintian warnings.
Fix LSB comment block (lintian warnings "init.d-script-has-bad-lsb-line")
Fix lintian warning "manpage-has-errors-from-man":

W: fadump1090: manpage-has-errors-from-man usr/share/man/man1/dump1090.1.gz  Empty input line #84