[Vim] Set breakindent option

Introduced in patch 7.4.338:
https://groups.google.com/forum/#!topic/vim_dev/qrhUA-dt7SY
[Vim] Update custom vim-skeleton config for 0.2.0
[Vim] Add preamble to vimrc
[Vim] Finish Switch settings for Markdown file type

Fixed TODO-style switching and added "--/++"- and "- [ ]/- [x]"-style
list item switching.