Add Instant Markdown plugin for Markdown editing with a (browser-based) preview
Add Julia syntax highlighting
Add Tmux Navigator plugin

When properly configured this allows for seamless navigation between Vim
splits and tmux panes
Add common dependency folders which should not be included in Ctrl+P

JavaScript projects (amongst others) tend to contain folders with
dependencies installed into them. These are typically not edited, but do
significantly increase the load time for the Ctrl+P plugin.
Fix whitespace at end of and within lines
Ignore plugins installed through Vundle