add unit test for issue 550
work in progress
progress
progress
added Serializable interface to Pair class

In order to serialize an ArrayList of CommonTokens without errors
progress
progress
progress
Added name to contributors file
Merge pull request #745 from sergiusignacius/master

Added name to contributors file
progress
test templates complete
generation of TestLexerExec for Java
add missing test in LexerExec, fix LexerErrors
validated SemPredEvalLexer
validated CompositeLexers
validated Sets tests
validated ParserExec tests
validate ParserErrors tests
validated CompositeParsers tests