Test, implement, verify QBluetoothLocalDeviceAdapter on Android

Connected devices and various pairing elements are still
missing.

At the same time temporarily disable existing Android
code for other API's.

Change-Id: I9b1de199fda6cbdf54f36ee6f6db433bc21ed310
Reviewed-by: Alex Blasche <alexander.blasche@digia.com>
Delete JNIThreadHelper and general code cleanup

JNIThreadHelper is no longer needed. We can use QAndroidJniEnvironment
instead.

Change-Id: I0a854910edfc882a0c6b60e5795f3ea9acb6229b
Reviewed-by: Alex Blasche <alexander.blasche@digia.com>
Git ignore the various json files required for Android deployment.

Change-Id: I1843f847c03f377c533f7c987163f89dbfaaa566
Reviewed-by: Alex Blasche <alexander.blasche@digia.com>
Fix hostmode transition from Discoverable to Connectable

Android cannot change to Connectable mode while in discovery mode. This
change circumvents the problem by turning bluetooth off and subsequently
on again.

Change-Id: Idb6be7c3702d9ef1853795e96d9aee6571d8413f
Reviewed-by: Alex Blasche <alexander.blasche@digia.com>