Become version 0.0.4 - with improvements and changes to optons files

- Use '!' as the options file directive prefix in place of '#'
  i.e. #include becomes !include, #ifdef becomes !ifdef and so on.  This
  removes some confusing syntax where directives and comments met and
  permits directives to be indented inside conditions.

- Allow the `!inherit` directives to define the, base, filename of the
  file to be inherited in addition to defaulting to the name of the file
  containing the directive.

- Convert path supplied to FindFileFromDirectory to an absolute path name
  to stop infinite loops when setting up the paths vector.

- Small code cleanups, remove an unused error and define directives as
  constants.

- Add more comprehensive tests for options read and file finding.

- Bump the version # to 0.0.4 - note, we're still "alpha" (pre version
  1.x) otherwise the '#' -> '!' change would mean a major version change.

Fix FindFile

Make it work as intended and restore the Go-like search for
platform/architecture specific files.

Extend find_test.go (a bit) and make it work.