Removed confusing cursor keys sentence

As suggested by @lurch, removed a sentence from the vim section which was contradicting the cursor keys section in the vi section.
Update linux.md

`sync` doesn't need `sudo`
More vi/vim/gvim changes

Made executable names for vi, vim, and gvim explicit in the prose, added a sentence pointing at vimtutor. Also tweaked keys to have a common style
s/VLC/VNC
Correct exit keystroke

Because Dave fails at multi-tasking :)
Fix license footer

It should refer to documentation, not learning resources