rename HDF5_*_LIBRARY to HDF5_*_LIBRARIES

This makes sure that netCDF plays nicely with FindHDF5.cmake
from CMake.

Conflicts:
	liblib/CMakeLists.txt
nc_test explicitly uses libm
move macro defintions behind option settings

This allows us to access HDF5 variables in the macros.
tests are using HDF5 explicitly, so link against HDF5
The call to h5cc (used to determine the hdf5 version) was not working properly on OSX or Ubuntu 14.04. Replaced with a similar call.  Also modified the call to use h5pcc in the event we are on a parallel system.
re: NCF-318
Fixed bug in ncgen. When classic format was in force (k=1 or
k=4), the "long" datatype should be treated as int32. Was
returning an error.
re: NCF-318
Fixed bug in ncgen. When classic format was in force (k=1 or
k=4), the "long" datatype should be treated as int32. Was
returning an error.
Removed some useless code
Partially deprecated varm function
test pnetcdf
re NCF-319

The pnetcdf support was not
properly being used to provide
mpi parallel io for netcdf-3 classic
files. The wrong dispatch table was being
used.  The fix was to modify
dfile.c#NC_check_file_type to properly
specify the pnetcdf dispatch table when
use_parallel was true.
Merge branch 'link-what-you-use' of https://github.com/nschloe/netcdf-c into nschloe-link-what-you-use
Merge branch 'nschloe-link-what-you-use'
Merge branch 'cmake-hdf5-variable-names' of https://github.com/nschloe/netcdf-c into nschloe-cmake-hdf5-variable-names
Merge branch 'nschloe-cmake-hdf5-variable-names'
clean up nc_test4 CMake syntax

This mostly means replacing
```
SET(VARNAME ${VARNAME} xyz)
```
by the more efficient
```
LIST(APPEND VARNAME xyz)
``

Conflicts:
	nc_test4/CMakeLists.txt
more LIST(APPEND ...)
LIST(APPEND CUR_EXTRA_DIST ...)