Major In ODATA-225 we moved function definition out of the EntityContainer by introducing a new Function element. We should take this opportunity to clean up the confusion between actions (which may be side-effecting and are not composable) from functions (which must not be side-effecting and may be composable). Previously these were differentiated by an isSideEffecting attribute on the FunctionImport, and depending on whether this was set other attributes (like isComposable) were or were not valid.