Updated BLPAPI to 3.7.9.1 (Linux/Windows), 3.8.1.1 (OS X).

Updated documentation to refer to the new version numbers and URLs
for the website and documentation.
Merge pull request #27 from apaprocki/blpapi-3.7.9.1

Updated BLPAPI to 3.7.9.1 (Linux/Windows), 3.8.1.1 (OS X).