Improve ignore file

Ignore the files generated by running build/gnuauto/setup.sh.
Explicitly define option values

This change specifies an explicit integer value for each option.
This should improve compatibility with clients that use the
dynamically linked library (e.g. TidyManaged). Otherwise when new
options get inserted the following options get new values which the
client doesn't know, so it tries to access it with the old value
which might fail because that value now is a different option with
probably a different type.
More explicit definitions of enum values
Remove autogenerated Makefile

Running build/gnuauto/setup.sh will re-generate the Makefile.
Print end tag for self-closing tag

When we output HTML5 and we encounter a self-closing tag we have to
output an end tag to be standard conform.

This fixes issue #111.
Some cleanup

- Update .gitignore file
- Update README.md to include instructions for Windows
- Remove obsolete README.html file
- Fix target name for DLL project
Remove hardcoded accessibility output
Resolved conflicts in packaging and enums merge