fix inputrc issue

Was printing escape code for ctrl-arrows. Fixed by including
/etc/inputrc (found this randomly while looking up something
else).
Add 'sd' and 'gd' bashrc aliases.

These allow you to (s)ave a (d)irectory into an environment variable and
then later (g)et it back. Could theoretically do this with pushd and
popd, I think, but this is much easier. Also, I do know about 'cd
-'--but I have a nasty habit of needing to change two directories away
and then losing the directory on the stack. This stores in an
environment variable, so it won't be lost unless you actually close the
window (in which case you clearly don't need it anymore, do you?).