The following are changes to fix#303:
1. hashsum pulls 512KB chunks of the file into memory. This ends up taking 1MB with
a secondary buffer allocated for windows. hashsum is now able to hash files larger
than the computer's available memory.
2. Text no longer transforms to UTF-8. This allows hashing to work on binary files
without specifying text mode. On Windows, it converts a Windows newline '\r\n' to
the standard newline '\n'.
3. Set default modes: Windows uses binary by default, all other systems use text.
Gil Cottle <gcottle@redtown.org>
* 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>
