Test cleanup plus a few new tests.
Add Get-PSReadlineKeyHandler

To make it easier to see what keys are bound, you can use the command Get-PSReadlineKeyHandler.

The command Set-PSReadlineKeyHandler also adds support for binding Ctrl-X prefixed commands in Emacs mode.
Merge branch 'master' of https://github.com/lzybkr/PSReadLine
Add api to get token/ast buffer state.