EventSender: send KeyUp events.

Some tests rely on that.
DRT: restore a few more parameters between tests.

* Avoids some silly failures.
MediaPlayer: smarter handling of missing data

* Do not lock the application when waiting for media to download
* Try to identify media every 512K of received data, until it's done
without reading any non-downloaded data
* Prepare for using range requests for faster download of missing bits.
Adjust for DataReceived API change

* Prepare for upcoming range requests support.
* Needs matching change on Haiku side.
Install the jsc shell.

A js interpreter on Haiku could be useful. Have fun!
Bump version to 1.3.0.