Rename ATC/atis.[ch]xx to ATC/atis_mgr.[ch]xx, to avoid confusingly
having 2 atis.cxx and 2 atis.hxx in the source tree. Also fix a copy
and paste error in src/ATCDCL/CMakeLists.txt.
This patch removes the conditional compilation of ATCDCL, compiling both
the old and new ATC systems. The old system only provides ATIS, AWOS and
some dialog lookups, and hence should not conflict with the new system.