Fix for hashsum: fix file checking #305

* Changed line verifications to use regular expressions.
* Added binary marker to output and start using the marker from
    the check file line as input to calc_sum
* Convert characters to lowercase before comparison in check

Gil Cottle <gcottle@redtown.org>
fix comment
Fix typo and code formatting
Merge pull request #306 from redcape/regex-hashsum-check2

Fix for hashsum: fix file checking #305