final draft, almost working match
fixed escape bug in insert_concate_op () & now it's up & running for the input_regex.txt regexpressions
- Added the flex rule file & it is working for the grammar we have
	assumed for the main.cpp as input
- TODO:
	Change the power of our lex program to that of a typical DFA
		i.e. NO NEED TO IMPLEMENT MAXIMAL MUNCH
	Keep both the versions of the lex program
		1) Current(implementing Maximal Munch)
		2) Bare Bone DFA one