Added option to compile a free or paid version

Changing the value of the variable 'client' to 'consumer' or 'personal'
in background.js either enables or disables YASB to require an activation
key. When enabled, the software will require an activation to function,
allowing the option to sell YASB. These modifications need to be done
before compiling source.

Some code has been rearranged for clarity.

[Closes #3]
Version number in footer updated automatically

Added an automatic way to update the version number in the footer of
options.html instead of manually updating it every time I update the
version in the manifest file.
Updated Readme to reflect changes in v.0.2.0

I organized the Readme and added instructions on how to use either the
personal, or consumer version of YASB.