Add the vimrc file

On top of this .vimrc file, any new changes/improvements will be introduced.
With this .vimrc file, and the required plugins installed, the Vim
environment has the following features that are necessary for a usable
IDE:
* Nice color scheme (Solarized)
* Convenient mappings for moving between windows
* Buffer (generic: opened files) navigator (MiniBufExplorer)
* Filesystem navigator (NERD tree)
* Source code browser (Taglist)
* Syntax checker (Syntastic)
* Python specific settings (including code completion with pydiction)