Bug fixes and improvemets

- Bug fix in 'spAction' directive. Changed priority to 500.
- Bug fix in 'spfieldControl' directive with the 'ExtendedSchema'.
- Bug fix in 'spfieldFocusElement' directive. Avoid to add the same
element when compile directive due to multiple $digest cycles.
- Bug fix in 'spform' directive. Added 'originalTypeAsString' and
'isVirtualField' properties to the field schema if needed.