Diaphora 3.1.1

This is mainly a bug fixes release that, however, includes 2 new heuristics and some experimental enhancements to try to find patched vulnerabilities when doing patch diffing. Here is the whole change log:

DIFF: Added a ratios cache to speed up comparison operations.
EXPORT: Added a column to save how long it took to export a single function.
EXPORT: Use cur.executemany() instead of cur.execute() whenever it's possible.
GUI: Added menu item "Show assembly patch".
HEUR: Added heuristic "Related compilation unit" to find functions by matching potential compilation units.
HEUR: Added heuristic "Same constants related matches" to find functions using the same constants in different places.
MISC: Refactored the code for finding potentially fixed vulnerabilities.
MISC: Replace multiple "SELECT *" appearances with just the required fields, where appropriate.
VULN: Added a few new patterns to try to find potentially fixed vulnerabilities.
VULN: Added heuristic to try to find fixed signedness issues for x86 and ARM.
BUG: Diaphora was calling ida_lines.get_srcline() for every assembly line. Fixed by doing it once per basic block.
BUG: The code for calculating the primes assigned to a compilation unit was terribly slow.
BUG: The microcode instructions list was built a lot of times instead of being done only once.
BUG: When importing pseudo-code comments, do not set the treeloc_t.item_preciser_t member itp when the stored value is None.