Added command line parameters for specifying the date and URL

Date is specified by the --date flag and is required.
Url is specified by the --url flag and is also required.

A help flag is also provided and is displayed when invalid
parameters are passed to the program.

Used Hideyuki Tanaka's parameter parsing library to add this
functionality with minor modifications to remove member
variable shadwoing warnings. Original source code can be found
at https://github.com/tanakh/cmdline.