Fixes for slick-extensions

- shorted column names in tests to <= 30 for Oracle
- remove default schema PUBLIC for H2(?)
- accept integer or char 1 and 0 for mapped non-native booleans
- special case integer and date tests to include oracle (should may be handled via a capability at some later point in time)
- introduces rawDefault method to allow preprocessing the default value meta data (for simplicity in slick-extensions)
I think the right way would be a TestKit capability that is enabled by default. We can still do that after 2.1.0, it should be binary compatible.