Rewrite

Move to single binary and no longer support symlinks.
Split code to multiple files.
Simplify build system, no more 'configure'.
Use variable for binary name
Remove unused errno.h include
Add missing newline(s) at eof
Update examples to new binary name

And some miscellaneous fixes.
Update information after rewrite
Simplify returning errors, add warn() and fail()
Put the function return type above it's name
Make run_regex function static

The are no external calls to it and it is not specified in the header.
Remove extraneous newlines