Move to beginning anf end of lines uses screen lines

* Open a file with long lines
* Soft wrap 
* Hit end at the beginning of a long line

It moves to the end of the buffer line. Super frustrating. 

So the select to the end/beginning, and delete to end/beginning both use screen lines, but this uses buffer lines.

This pull removes the beginning / end of screenlines commands and moves the canonical commands to use screen lines. 
I'm still down for having them as commands, just with no default keybindings.

Perhaps @nathansobo has feelings as well on this.