Added IMA SDK events and improved focus handling

NEW: Added IMA SDK event constants
CHANGE: Return focus also on IMA SDK event CONTENT_RESUME_REQUESTED
CHANGE: Clear active element after focus has been returned

Return focus to canvas when returning to game after ad

FIX: Return focus to the Defold canvas element when returning to the game after an ad has been shown

Load SDK early

CHANGE: Initiate load of GDK SDK before loading Defold

First public release

1.0.0

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