Adding some new functions to the calculator.

[saransh484]

I have added these two functions, binary to decimal and decimal to binary conversion to the calculator. please assign me this issue.

[subhranshuchoudhury]

@saransh484 when adding new functions to this calculator. please declare those buttons inside the other function div. By doing this the responsiveness will be there.

[saransh484]

Thanks for the advice, I'll keep that in check.