Addition [pull?]: Support IsComputed property in SQL Server, and don't update/insert those

[awbacker]

These two commits add awareness of Computed columns, to the templates and the core.

• Computed columns can still be updated in code
• Core will not try to update/insert a column that is computed
• Future
  • Should make computed column property "protected set"
  • Should not mark the column "changed"

http://github.com/awbacker/SubSonic-3.0/commit/e8141cffb4c5a6c22269f402c7e08dcfc8ff6c23 http://github.com/awbacker/SubSonic-3.0-Templates/commit/d32b69f8f4a484c77567207a071f0caa46038701

Sorry about the CS files in there, don't know what to do bout that since I am so new to GIT.