replace vim-ipython by subtree merge
add custom snippets and screen maps & minor update

* snippets for cpp, tex and cmake
* screen maps for cpp and tex
* untrack & ignore pyc
* ignore tags
* add additional spelling db
add recent work on my own plugins
subtree add vim-glsl.
update commentor and gitignore, add ricoh-glsl

ricoh-glsl mixes in cpp filetype for glsl files
(for commentor and snippets)
bugfixes in Commentor class.
add R support to commentor.
Add Vim-Markdown-Extra-Preview (via read-tree).
add a way to open r interpreter

so it actually opens in vim's working dir.
Also, vertical split workaround for r-vim.