Add sourceSave() and sourceDelete() methods notifying plugin implementers of a source being saved or deleted. Minor cleanup on sourceForm().

#701432 pounard, Will White: PHP 5.3: array_shift() expects parameter 1 to be array, null given in (...).

Throw appropriate errors. Add an @ to suppress debug output when SimpleXMLElement constructor encounters problem. Output exception message (on FeedsSource level) instead.

  FeedsSimplePieParser.

  formalize feed elements.

This is a preemptory step to enable cleaner result handling and prepare the ground for Batch API use.

Throw exception when download fails.