Update .vimrc with autocommands

Added the following sections:
* Disable arrowkeys
* Split navigation
* Save with ctrl+s
* Rename file macro
* Intelligent tab trigger
Proper pasting in VIM
Add <C-T> as alias for file navigation
Unix line endings for .virmc commands
Listing all stuff to ignore individually

This looks a lot worse than the previous solution, but is _much_
faster.