Add missing extern "C" blocks and move to after headers.

If extern "C" blocks are before external includes, you can end up with broken
interfaces if the external include is doing anything C++ specific.
Move standard includes to before any local includes

This prevents any "side effects" from the internal includes breaking the
standard libraries.
Added adios_transform_..._is_implemented() functions to all transforms.
List transform methods that are actually active (all of them always exist, just are "unimplemented")
Merge pull request #20 from chuckatkins/cxx_fixes

Cxx include fixes from Chuck Atkins @ Kitware
include netcdf_par.h in NC4 method (required since netcdf 4.1.2)
improved help on -m option for adios_config
fixed potential memory leak...
remove the single space from MPILIBS which signals the success for testing MPI
fix AC_ARG_WITH[portals] to avoid getting mxml libs duplicated in LIBS
fix AC_ARG_WITH[infiniband] to avoid having mxml directory in INFINIBAND_LDFLAGS
print "=== Checking for Cray ugni/pmi..." when we are actually checking for them
regenerated configure
regenerate configure again
include sys/types.h for this example code (address Magda's compile problems)
runconf fixes on titan and chester
removed unnecessary timing stuff from reader code.
added adiosVM section to cmake_init
implemented bounding_box reads for scalars. fixed FFS issue tagging a
float as a double.
Merge branch 'master' of github.com:ornladios/ADIOS