vim: Improve scratch buffer mappings
vim: Remove ShowMessages() in favor of vimple's :View
vim: Add python-mode plugin
vim: Add vim-dentures

vim-dentures provides text objects for indented blocks, such as python
blocks.
git: clean up tree alias

The --no-pager part is redundant now that core.pager is `less -FX`
shell: add ~/bin to $PATH
vim: rst formatting shortcuts