Fixed http://rsdn.ru/forum/prj.rfd/5172906.
Added default constructor to EditableArrayList..
On a Nullable Field a TimeSpan could be Null.
Look for Null Value in TimeSpan BigIntMapper
If DBType of a Field is set, use it in BLToolKit,
If not, A Insert to a Binary Field in MsSQL will fail
Code cleanup.
Implemented #238.
Fixed https://github.com/linq2db/linq2db/issues/20.
Merge branch 'master' of https://github.com/igor-tkachev/bltoolkit

Conflicts:
	Source/Data/DbManager.cs
	Source/Mapping/MappingSchema.cs