[Python] Adds a convenience dialog. Dialog.notification()

[Python] Adds a convenience dialog. Dialog.notification()

changed the way this works. searching around the source i determined DefaultIconInfo.png isn't how XBMC actually determines the default icon.  XBMC uses id numbers in DialogKaiToast.xml.

The user still has the ability to pass their own image for icon.

[Python] Adds a convenience dialog. Dialog.notification()

PyDocs fixup.

Switch to DelayedCallGuard()

Use getters for type check.

Default time to 0 since we use TOAST_DISPLAY_TIME as default.
Merge pull request #2627 from nuka1195/Branch_Python_Dialog_notification

[Python] Adds a convenience dialog. Dialog.notification()