Restrict calculation for very long passwords

Limit the full entropy calculation to the first 100 characters of a password. Entropy of the remaining characters of a long password is calculated as if they were a single incrementing sequence.

Spacial test update.

Include updates to spacial tests from github user Perlbotics.
Fix clang compile error.

v2.3: Revert commit 3552fedeb2f485b2cba8d04a4ef6262fd9dffd1c.

Clarified the licensing of contributions made from pull requests.
There is no C/C++ code change in this release.

v2.2: Merge pull request #14 from dhenot/master

Main purpose for this release is to include heap buffer overrun fixes found by GitHub user dhenot.
Testing with AFL fuzzer hasn't shown any other similar problems, but there could still be some as fuzzer testing never finishes..
Also changed to using the MIT license & some minor file tidying as suggested by other GitHub users.