Merge pull request #1 from pohuigin/master

Added functionality to allow inputting a mag image, mag index, igram image, and igram index, and skipping the processing, in addition to being able to input a mag and int filename
changes
merged with paul's version
 Adding some comments, etc, after merging with paul's version.
Modified umbsel() --going ahead with ahead with paul's version.
Modified comments to include explanation on keywords.
minor changes
Major changes in find_delta
changes
minor changes-removed print statements that was used for debugging.
added files to ignore