Added csv_handler in modules dir
Support for the 'modules' build

Modified configure.ac so that it will build the Makefiles for all of
the modules in the new modules subdir. Added 'subdir-objects' to the
Makefile.am files in the bes build that need it (to suppress the wordy
warning message). Also added .gitignore.
Added more handlers to the modules branch

Tweaked the configure.ac file so that dap-server now builds; the
configure script now has some new makefile variables for handlers
to use when linking unit-tests. I added the dap-server, fileout_json,
freeform and xml_data handlers to this branch.
Changes in the modules dirs for csv and dap-server.
Added fileout_json to the modules build.
Found and fixed the ResponseCacheTest error.

The problem with the ResponsecacheTest unit test was that it
depended on the 'response_cache' directory already existing. But
git does not (it seems) fetch/update/etc. empty directories. I
added a .gitignore file in the directory and set it to ignore
everything except the .gitignore file.
Configured submodules to use the 'modules' branch

I editied the .gitmodules file so that csv, fileout json and
dap-server call should use the 'modules' branch by default when
cloned using the bes 'modules' branch.
Added the freeform handler to the modules build.
Modifications for the modules build.

Added the Freeform and xml_data handlers. The dist target works, as
does make install.
Added netcdf_handler to the bes modules build.
Added fileout_netcdf to the BES modules build.
Added gateway_module to the BES modules branch/build.
Modified .gitmodules so that it tracks the modules branch of
gateway_module by default.
Added fieout_gdal to the BES modules build
Tweaked the xml handler module given that hdf4/5 are not yet working.
Fixed configure.ac so that FOUND_OPENJPEG is defiend even if BUILD_GDAL
is not.
Fixed configure.ac when --without-dap-modules is used.
Added the fits_handler to the bes modules build.
Added gdal_handler to the bes modules build.
Added the *.conf files to git ignore