Vim: Refactor bundles into their own file which is sourced in the vimrc

Refactor:
 * Vim bundles into their own vimrc.bundles file which is sourced in the
   vimrc file
Improve installer to handle directories and general improvements

Add:
 * Recursive directory handling when symlinking (ensure all files within
   source directory are symlinked individually, oppose to the directory)
 * New way to symlink directories/files (recursive approach)
 *

Fix:
 * Dry run to actually work as expected

Refactor:
 * Ouput messages to be more consistent
 * The use of using File module to using Pathname instead for source and
   target (therefore they are Pathname objects)