.bashrc: reindent completion if-block

.bashrc: write out a proper if-else-fi block instead of x && y || z

.vimrc: signify is OK

.hgrc: have a committemplate and use it in .hgeditor for showing diff

.hgeditor: modernize syntax and fix shellcheck warnings

.hgrc: strip extension by default, stripout alias

.vimrc: faster last buffer switching

.vimrc: make ctrl-p ignore more files

.vimrc: ctrl-p for open buffers

.vimrc: only store buffers in session