Remove faup1090 Makefile ref to coaa1090.obj

* It isn't needed.

* Also include /usr/share/dpkg/buildflags.mk in Makefile and makefaup1090
and add our compile-specific CFLAGS to the CFLAGS that sets up
so we compile with the preferred Debian build flags.
Merge branch 'master' of github.com:flightaware/dump1090_mr