[Fix] Nullable types in ExecuteScalar
Merge pull request #85 from MontakOleg/nullable_execute_scalar

[Fix] Nullable types in ExecuteScalar
Added support for default values

Exception is not longer thrown when you add a column with NotNull and
the table already exists. this requires Default attribute.
Added test for DefaultAttribute
Corrected Test
support overriding generated type #91
adding something that can be compiled without licenses
make appveyor happy plx
uint64 too #91
without yaml intro
Merge pull request #93 from haf/feature/extra-type-mappings

Feature/extra type mappings
Merge pull request #87 from tyrongower/master

Added support for default values