README.md: fix gittip link
let Emacs adjust point

Previously we did adjust point ourselves, because "Emacs often leaves
point in invisible regions, it seems."  However we did not actually
succeed in doing so because `disable-point-adjustment' is only set to
nil when a Magit mode is turned on, not for each and every command that
could possibly be run in a Magit buffer.  But that variable's doc-string
reveals that this doesn't have the desired effect:

  After a command is executed, if point is moved into a region that has
  special properties (e.g. composition, display), we adjust point to the
  boundary of the region.  But, when a command sets this variable to
  non-nil, we suppress the point adjustment.

  This variable is set to nil before reading a command, and is checked
  just after executing the command.

So I am removing our code that does the same, doing so does indeed not
change the behavior.
Merge branch 'pr/native'