Stubbed the combine command port

Most flow is there but no file checking is done.
Montage command is not executed and not all required variables make it
into the command.
Combine functionality is impelemnted

Splitting the deep zoom script into a generic command line utility, a
core library, and the implementation.

Combine works as far as I can tell. The command line prompt for it is
not correct currently and needs cleaned up. It operates entirely
synchronously right now.

Fixed a bug with maxlevel calculation. Google claimed log(2) was ~0.3…
and I used that as the constant creating zoom level 38 when it should
be 17 for the test data set.
Updated read me
Merge branch 'dev-null' of https://github.com/jbaicoianu/deepzoom-nasa-utils into dev-null

Conflicts:
	README.md