Support some accidental shift-key to act like key

Apparently people accidently hit Shift+Backspace often enough that it's annoying
when it doesn't delete the previous character.

To fix this - we'll pretend shift wasn't pressed if we see unbound keys where
the character is a control character, but the only modifier was shift.  Realistically
this is just Backspace because Shift+Return is bound, but maybe there's another
I'm missing.
Update changes.txt
Rename *Word functions to Shell*Word

The implementation of the various *Word functions more closely matches Bash's Shell*Word so I've renamed the functions.

The next step is to implement the configurable character based word boundaries.
Add delimiter support in *Word related functions

Functions including:
  * NextWord (Windows mode)
  * ForwardWord (Emacs mode)
  * BackwardWord
  * KillWord
  * BackwardKillWord

now use delimiters instead of being token based.  The
delimiters can be specified by

    Set-PSReadlineOption -WordDelimiters "..."

To see the current set of delimiters:

    (Get-PSReadlineOption).WordDelimiters
Update changes.txt.