Update ax_blas.m4 to serial 14

This adds support for OpenBLAS, among other things.
Prevent overlinking to BLAS/LAPACK
Improve the pkg-config file

Get the library name and URL from configure.ac.
Make the description an actual description.
Remove the empty Cflags.
Remove an extra trailing '/'
Remove two unnecessary automake variables

Fixes the following autoreconf warnings:
EXAMPLES/BAND/Makefile.am:84: variable `snband_SOURCES' is defined but no program or
EXAMPLES/BAND/Makefile.am:84: library has `snband' as canonical name (possible typo)
EXAMPLES/BAND/Makefile.am:86: variable `snband_LDADD' is defined but no program or
EXAMPLES/BAND/Makefile.am:86: library has `snband' as canonical name (possible typo)
Don't install the examples
Link libparpack to libarpack

Avoids having a duplicate copy of libarpack inside of libparpack, thus
saving disk space.