Created Tokenizer branch
Worked on inital version of Tokenizer. However there are some bugs in it. It seems like it is not processing the whitespaces and the numbers correctly
Fixed bug in handling numbers and whitespace with the tokenizer.
Also, fixed the bug in operator separator
Added the semi_colon to the operator. (We may be have to later
discriminate between the punctuator and operator. However, lets make
that handled by the parser, not the tokenizer)
Just added some comments. I commited in order to merge with master branch