Show `ProgressDialog` while reconnecting to a device from the `DeviceControlActivity`

[tfKamran]

Fixes issue #8

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[tfKamran]

I've already signed it, if not my email account, then at least my GitHub username should have matched.

[mitchross]

@tfKamran you need to reply "I signed it!"

[ryanseys]

No, some of the commits just don't have an email (you can see this by seeing the commits aren't associated with an email in the commits panel of this PR).

Or just look at https://github.com/googlesamples/android-BluetoothLeGatt/commit/3556ca61044c4ddf49317c0ab9c8c4897e1657c9.patch and see that the commit doesn't have an email in the From field.

[codingjeremy]

I am closing this issue/PR, as it has been migrated to the new repo linked above in the comments. Thank you!