modified while.isa for translation
seperate while loop and do-while loop
implement translate for WhileStatement and DoWhileStatement
add a simple_switch.isa test
add DefaultStatement
add SwitchGenerator
add LoopOrSwitchStackList
modify 'translate' of ContinueStatement
implement translate for SwitchStatement, CaseStatement and DefaultStatement
remove trailing blanks
add testcase conditional_statement
implement translate of ConditionalExpression
rename symbolTable to variableTable, which is more appropriate