Add support for JDBC drivers which don't support generated keys

[andeee]

• Not every JDBC driver does support getGeneratedKeys, in my example Sybase SQL Anywhere doesn't support it and throws an SQLException when e. g. trying to conj! onto a table
• We can make clojureql work with these drivers when calling supportsGetGeneratedKeys onto DatabaseMetaData before we create the statement and append the generated keys to the result
• I also check for the corner case when supportsGetGeneratedKeys isn't even implemented, catching the AbstractMethodError.
  Support for generated keys was introduced with JDBC Version 3, so here we could start to support even older drivers - tested with a SQL Anywhere JDBC Driver Version 9 which only supports JDBC Version 2

[andeee]

follow up from #107

[bendlas]

Committed. Thanks a lot for your help!