Got Query and DoubleQueries working

Added a Query and DoubleQuery class
- supports <,<=,==,>=,>, != operators
- can both be used in parts of larger queries
- added database support for queries
- added query operators OR and AND
- framework for adding more query operators in place
- added tests for single queries and a double query
- more tests would be useful on a unit test level
Added MultiQuery
- Needs tests
- Not currently functional
- Will support N queries and a single operator