LT_INIT is supported only on Libtool >= 2.0, so I reverted it to
using AC_PROG_LIBTOOL.

Also reorganized how the common libraries were being built. Now
they are treated as libtool convenience libraries instead of
installable libraries (the --with-singlelib configure flag can
still be used to generate a combined, installable DSO)

I cleaned up the set of files being installed by automake, so the
list of things we need to remove before packaging the RPM is now
only the .la files associated with our own plugins.

Allows building shared or static libraries using autotools and
provides a pkg-config file to simplify inclusion into other parts
of the project (or other projects in the future)

For now, we will statically link the collection library and INI
parser.