getting log for single file in tree view
add aliases for cd Downloads, cd src
add option --all to tig to show all branches by default
add method to append a path to $PATH
several additions/fixes

* unbind C in refs view for checkout of branch
* add files to index in stage view as well
* add copying of the hash (short and long) to shortcuts (y/Y)
* add c as checkout key in branch view
clean up of unused stuff
disable F4 to inster current filename
add command-t module (make sure to have vim be compiled with system's
ruby version
)
add F4 mapping to toggle between absolute and relative line numbers
remove unused method