rtags

I just submitted a patch for rtags.

rtags overwrites the existing TAGS file by default.
This patch adds an option "-a" or "--append"
so that rtags will append to the TAGS file instead of overwriting it.

This will allow rtags to index an entire directory (e.g. rails app)
find rails_app_dir -name '*.rb' -print -exec rtags -a {} \;

I just ran rtags on /usr/lib/ruby. Took a while to finish. Let's see how useful
it is going to be.