Fix a minor bug in the lexer (it would not match the last character of the input) and add Lexer tests.

include/Lexer.h

@@ -16,9 +16,10 @@ class Lexer {
 		void addRegEx(std::string regExString);
 		void setInput(std::string inputString);
 		Symbol next();
+		static void test();
 	private:
 		std::vector<RegEx*> regExs;
 		std::string input;
 		int currentPosition;
 };
-#endif
+#endif