Added a function to strip ANSI escape codes from strings generated by test harnesses in order to ensure that JSON and XML formatted output does not cause problems for parsers.

The StripAnsi() function was added to otest-shim.m and has the ability to strip all ANSI
escape codes from output strings except for keyboard change codes, which are not relevant
to this scenario.
Modified to simplify regex string.
Merge pull request #142 from cpeterso87/task-2654386

XCTool strip ANSI escape codes from test output.