Begin complete reworking of the build process

Byfl previously inherited a lot of cruft from LLVM's build process.
Some of that is because Byfl was based on an in-source example, but
this adds an artificial dependency on an LLVM source tree.  This
revision is the beginning of an attempt to throw all that away and
start fresh with a proper autoconf/automake/libtool build process.
Corrected the way various files are generated

The configure script now fully expands @libdir@ in bf-gcc and bf-inst.
The longstanding circular dependency in opcode2name was resolved by
renaming the script to gen_opcode2name.
Honor silent mode in the tools/wrappers Makefile
Corrected "make uninstall" in tools/wrappers

Manually cleaned up everything installed by ExtUtils::MakeMaker, which
no longer supports "make uninstall".
Began adding support for parallel build trees

This version *almost* passes "make distcheck".  Just a little more
work to do...
"make distcheck" passes

The installation still isn't completely correct, but at least "make
distcheck" reports no errors.  Note that no regression tests have been
defined; "make distcheck" is primarily testing VPATH builds and
DESTDIR installs.
Further honor silent mode
Install the LLVM plugin as bytesflops.so not libbytesflops.*
Corrected linking

bf-gcc can once again compile and link applications, and these can run
with no dependency errors even if linked against the shared libbyfl
library.
Support --disable-shared

Added code to lib/bytesflops/Makefile.am to force libtool to build a
shared library even if the user configured Byfl with --disable-shared.
(LLVM plugins can be dynamically loaded into opt only if they're built
as shared objects.)
Wrote man pages for bf-gcc and friends

These appear in Perl POD format embedded within bf-gcc.in.
Shortened the README

Now that most of the usage information is in bf-gcc.in, there's no
longer a need for the README to be so lengthy.