0.14.7: Fixed ability to set a column to null in an update

If a value was nil previously the valuesByField dictionary
was being left without that key. Thise code now explicitly
inserts in an optional as a value.

Update to Zewo 0.14

No real changes to SQL, but this version is compatible with the rest of the 0.14 modules, many of which have gone through significant development.

0.13.0: Update to Zewo 0.13 (#17)

- Swift 3 updates
- Core as only dependency
- Repository cleanup

0.8.1

Add missing validate() in create(). (#11)

0.7.1

Fix warnings

0.7.0

Added protocol extension method

0.6.0

fix typo