* Created NCubeConnectionProvider generic interface for providing connection/persistence context and management.
* Created NCubeJdbcConnectionProvider for jdbc implmentation of NCubeConnectionProvider.
Added loadCubes and loadCube methods that take NCubeConnectionProvider.
Added test methods testLoadCubesWithJdbcConnectionProvider and testLoadCubeWithJdbcConectionProvider. Added getJdbcConnection private method for getting jdbc connections, which will replace getConnection method.
Merge branch 'master' of https://github.com/jdereg/n-cube
Removed startTransaction
Added doesCubeExist that takes NCubeConnectionProvider.
Misc refactoring of methods that take NCubeConnectionProvider.
Added addition check of "isValid" on jdbc connections in validateConnection method.
Merge branch 'master' of https://github.com/jdereg/n-cube
Added tests for testing NCubeJdbcConnectionProvider exceptions. Added to testDbApis for testing doesCubeExist using NCubeJdbcConnectionProvider.
Merge pull request #43 from crowland/master

Refactoring NCubeManager for NCubeConnectionProvider