Unify creation of auxiliary Vim directories

And store them in ~/.vim/data/.
Add gitignore file
Use https URL for cloning in the README
Squash two submodule commands into one in README
Add some filetype plugins

 - for Cool language;
 - for .gitignore files;
 - for flex;
 - enhanced C/C++ highlighting.
Add easydir plugin

Creates non-existing parent directories in path.
Add gnupg plugin

Automatically decrypts/encrypts GPG-protected files.
Add "tags" to .gitignore
Remove unused list of repos and updater script
Update return type placement in C snippets
Round indentation to multiple of 'shiftwidth'
Don't define my normal mode CR in vifm-edit buffer

"vifm-edit" defines its own meaning for the Enter key.