Overwrites a default vim binding of H as top line in the window
and Las bottom line in the window. Beginning and end of line are
available anyway as 0 and $ anyway.
Overwrites the default binding of C-i as a C-o counterpart for navigation through jump history. C-i/o are really useful and feels weird having one, but not the other. Also, you can open NERDTree easily with the tab shortcut anyway.
There's an issue with the second. The only reason Tab worked as :NERDTree was that it was mapped to ^I, which no longer opens NERDTree. I cna't find where it was mapped, though. Any ideas?