Fixed issue where string buffer would flush invalid column names if API endpoint contained trailing slash
Changed config to use global read/write defaults for cassandra consistency rather than column family configuration
Fixed error in default configuration
Merge pull request #27 from warmans/bug/cassandra-consistency-defaults

Changed config to use global read/write defaults
Updated how to build instructions to use correct tablesaw version
updated build number to 0.9.4
Merge pull request #28 from warmans/bug/how-to-build-instructions

Updated how to build instructions to use correct tablesaw version
Merge pull request #26 from warmans/bug/null-column-exception

Null Column Exception Caused by Invalid Tags reaching Write Buffer