ExpressionBuilder nullable char fields problem

when building expression, nullable char value was formatted as number
rather than char
Add InstantHandleAttribute to avoid "Access to modified closure" in Resharper
Added BasicSqlProvider.MaxInListValuesCount property to control InListPredicates.
Oracle allows max. 1000 values for IN lists.
Added BasicSqlProvider.MaxInListValuesCount property to control InListPredicates. Oracle database allows max. 1000 values for IN lists.
Merged branch 'master'.
Merge branch 'pr/n168_mkramar'
Fixed formatting.
Merge branch 'pr/n169_jack128'
Added more InstantHandle attributes.
Merge branch 'pr/n171_yallie'