Add ability to import without grades (just structure)

QA PASS - works as expected

QA READY - 1.8.0-a9

QAing - Pete

NOTES:

• Need to accommodate legacy, none-structured gradebooks imports for a while, per Jon G.

• Need to test for none-structured imports and generate an error explaining the problem, per Jon G.

• Import and Export naming "....Grading Template". this name implies to me that you are dealing with a gradebook either no grades, but structure of all items or filled out with grades in the items. In actuality this is the import/export of new item(s).

• Jon G. says much of this will be addressed in

• new param read by GradebookImportController for just structure import

• added params to various private methods in ImportExportUtility to pass the value

• added an UploadKey enum for value

• added Boolean setters and getters in ImportExportInfo and ImportSettings

• removed unnecessary else statements in various places in ImportExportUtility (where the statement 'else' was not strictly nec.)

• hide multigrid and expand item panel in importpanel when importing just structure

Code Review : http://codereview.appspot.com/5689074