[antlr-interest] fixed nasty DFA analysis issue

[Terence Parr]

Fixed:

http://www.antlr.org:8888/browse/ANTLR-178

ANTLR detected but failed to announce the error as it thought it would  
retry with k=1. It just didn't. ;) Did lots of clean up.   Added some  
tests; doing more now.  Will push a build later.

Ter
---------------
My changes:

December 13-14, 2007

* I abort entire DFA construction now when I see recursion in > 1 alt.
   Decision is non-LL(*) even if some pieces are LL(*).  Safer to bail
   out and try with fixed k.  If user set fixed k then it continues  
because
   analysis will eventually terminate for sure.  If a pred is  
encountered
   and k=* and it's non-LL(*), it aborts and retries at k=1 but does NOT
   emit an error.

* Decided that recursion overflow while computing a lookahead DFA is
   serious enough that I should bail out of entire DFA computation.
   Previously analysis tried to keep going and made the rules about
   how analysis worked more complicated.  Better to simply abort when
   decision can't be computed with current max stack (-Xm option).
   User can adjust or add predicate etc...  This is now an error
   not a warning.

* Cleaned up how DFA construction/analysis aborts due to non-LL(*) and
   overflow etc...  Throws exceptions now, which cleans up a bunch of IF
   checks etc...  Very nice now. Exceptions:
         analysis/AnalysisRecursionOverflowException.java
         analysis/AnalysisTimeoutException.java
         analysis/NonLLStarDecisionException.java

* ErrorManager.grammarWarning() counted them as errors not warnings.

* Unreachable alt warnings are now errors.

* The upshot of these changes is that I fixed ANTLR-178 and did
   lots of refactoring of code handling analysis failure.