apitrace: Added package

Add `apitrace` and `eglretrace`, for GLES debugging and profiling.

*Usage for tracing:*

    apitrace trace -a egl ./glquake

This will create a file glquake.trace in the current directory (by default).

*Usage for replaying:*

    eglretrace glquake.trace

There is also functionality for cutting/manipulating traces, for example to isolate certain frames, see `apitrace trim --help`.
It should also be possible to copy the resulting trace files to a desktop for examination using the qapitrace GUI (not yet tried).