re-enabling injectErrors unit test
bug fix in injectErrors fn

* returning error message as a new Message obj
exposing getD4 fn on Message obj
bug fix in flipBit fn

* Now allowing flipping of the D4 bit.
add clone fn to MessageSegment
flipBit fn now returns new MessageSegment w/ bit flipped
updating injecteErrors fn

* Now handling the new error message segments coming back from flipBit fn.
* Fixing unit test.
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