[CB-2666] Added check for null arguments.

If null arguments are received, send an error and an explanation.
[CB-2654] Delay executeScript/insertCSS callback until resources have loaded; pass JS results to callback
Keep the splashscreen image ratio instead of streatching it.
An ImageView is used to be able to use ScaleType.CENTER_CROP, which is similar to the background-size:cover CSS property
Fixup for CB-2654.
[CB-2908] Fix the DroidGap activity Lifecycle broken issue

Attempting to invoke the Activity's finish() onDestroy breaks an Activity's lifecycle
flag. OnDestroy can be called by the system, for instance, on restarting an Activity,
it's definitely different from a normal finish().
Finish() incorrectly in onDestroy results in another DroidGap derived activity
is started, while the original one is not yet onDestroy. This issue could be
found when the system is trying to restart the activity upon, for instance,
receiving immediately successive device Config changes.
Adding additional condition that the phone must be made by HTC for the setNavDump to be set to true to try and work around CB-2907, if it's still a problem on HTC devices running Android 2.2, that's just the luck of the draw.
Merge branch 'master' of https://git-wip-us.apache.org/repos/asf/cordova-android