rm print statement
resource leak fix from Coverity Scan
rm potential null ptr deref (Coverity)
make explicit that graphs must be EmptyContext, never null (Coverity)
avoid potential null ptr deref (Coverity)
rm unneeded null ptr check (Coverity)
fix cut-paste error (Coverity)
rm dead code (Coverity)
defined compareTo but not equals/hash (Coverity)
oops; deleted side-effecting "dead code"
change cast to null chk (Coverity)
rm dead code (Coverity)
consistent return of null for empty DFA (Coverity)
clean up equals/hashcode for Interval (Coverity)
avoid resource leak upon write() exception (Coverity)
dodgy code cleanup (Coverity)
avoid resource leak and cleanup (Coverity)
add note about Coverity cleanup.
Merge pull request #329 from parrt/master

Lots of little fixes thanks to Coverity Scan