Trying to deal with the changing size of a SrcSpan when doing
updateTokensForSrcSpan. Getting messy.
Introducing explicit flag to record that a SrcSpan size has changed,
and switched to bitwise encoding into the GHC.SrcSpan to ensure
fitting into 32 bit GHC
Progress. Slowly.
Seem to have broken getSrcSpanFor
Test set up, time to start fixing it
Finally tracked down the bug. Eq for ForestLine must ignore LenChanged flag.
Still something odd in getTokensFor
Making progress. Only re-align the tokens on final retrieval.
Making progress at last. Marked work point with compile error.
Tests pass again, at last.
Added missing expected test result file. Thanks Travis.