Change the 'H' mapping

This might break something. H step fields backwards but also stops at
where the content of the columns begins.

Look into this example (with the cursor being '|')

aaa,   bbbb,|ccc

Pressing 'H' moves to

aaa,   |bbbb,ccc

Pressing 'H' again moves to

aaa,|   bbbb,ccc

Pressing 'H' moves to

|aaa,   bbbb,ccc

While 'E', it would move directly to
aaa,|   bbbb,ccc

and then again:
|aaa,   bbbb,ccc