fix spelling.
Build fix for NetBSD and other systems where /bin/sh isn't bash

Fixed by explicitly using /bin/bash. Removing bash-isms would also
work. But /bin/sh is bash on most developers' systems, so using that
shell explicitly seems like it's less likely to break in the future.
Clarify legacy/current version info
Removed bash dependency in test/run_tests.sh and updated for NetBSD.
Merge pull request #83 from yep/fix-spelling

fix spelling
Merge pull request #92 from emaste/master

Clarify README with respect to legacy version
Merge pull request #82 from patperry/master

Minor changes to make "gcc -Wextra" happy
Merge NetBSD build fix (no BASHisms) closes #90