This attemps to partially implement MISB ST1608.1, "Transport of Motion
Imagery and Metadata over GigE Vision". This relies on GstKLVMeta, which
is currently a merge request 124 for gst-plugins-base. For now we
include it here. Currently all KLVMeta is packed into one chunk, no
special handling of timestamps is done. Testing has only been done
between pleorasink and pleorasrc, no other MISB-compliant stream.
Not the prettiest way to handle this, but we have a need for supporting
multiple versions of eBUS, and this way we can distribute multiple
versions. This also tries to modernize the FindPleora.cmake file.
