Added pathctl, fixed pushcd, retabbed files,

* pathctl is a set of functions for manipulating PATH
* .bash_aliases retabbed, ~ changed to $HOME and quoted
* pushcd
** Added comments
** Fixed `cd -` when the dirstack is empty
* .bashrc
** Retabbed
** ~ changed to $HOME and quoted
** Moved sourcing of .bashrc.local to the end of the file
** Fixed sourcing of .bash_functions.d
* .vimrc
** Turn on expandtab
*** On a related note, I've lost the will to live
** ~ changed to $HOME and quoted