[FIXED JENKINS-12821] android.device=emulator

The android emulator does not connect to ADB properly if used with
a non-4 digit port number

Update to port-allocator 1.8. This allows us to use the new allocatePortRange method. We allocate a group of 3 consecutive ports in the 4 digit port number range and hence work around the bug. Note that the two emulator ports should be consecutive numbers.

Tested on Ubuntu 12.04 with android-maven-plugin. Use -Dandroid.device=emulator to select the emulator.