Fix conversion from string=>ConsoleKey for digits
Merge branch 'master' of https://github.com/lzybkr/PSReadLine
New tests
Simplify tests with a different test hook
Refactor code to multiple files
Refactor test code to mirror code to test
Fix cut/paste typo
CancelLine tests
Avoid hanging when a test fails

A recent change to the test framework moved calling the validation
actions to the thread that reads keys.  If an exception occurs on
that thread, the test would hang.

Instead, we'll catch the exception and throw it from the main test thread.
Add some begin/end of history tests
GotoBrace tests
Exclude debug code from code coverage
Fix DigitArgument bug

Multiple Alt+- before any digits would cause an exception.
Cleanup extra usings
DigitArgument tests
ScreenCapture tests