version 0.6:used recursive call of salveExpressionInBrackets
readme & build file changed for version 0.6
version 0.6: test for Integers & decimal (positive & negative) created and running successfully
evaluateExpression method: added one if condition of checking for brackets
readme file changed for release 0.6, release 0.6 completed successfully
more test added for evaluator method to cover every if in evaluator method