Updated the bashrc file.

The wduchain function becomes an alias with just the actual DUChain cache
path. Moreover, I've removed the "g" function, since exporting the CDPATH
environment variable seems to work as well. Also remember that we need
the bash-completion package installed so Bash can autocomplete directories
under the CDPATH.
Putting the "g" function back to the bashrc file.

I tried to do fancy stuff with the CDPATH and a directory with symlinks
inside, but it didn't work the way I wanted. So the "g" function is back.
I've also removed some shortcuts that are not needed.
Added some stupid aliases around the cd command