This gives the framesrc the ability to produce a continuous stream of data
from disjoint segments.  The framesrc is provided with a single frame cache
as usual, and a seek is performed to the desired start time of the stream
as usual.  If a segment list is provided, only data from the intervals in
the segment list will be read from disk and pushed downstream.  The
intervals outside the segment list will be pushed down stream as gaps.  If
no segment list is provided, all data is read from disk and pushed down
stream.

When using the segment list feature, the gap/non-gap transitions might
result in short buffers being produced, that is buffers smaller than block
size will be produced in order to align their boundaries with the segment
boundaries.  No buffers larger than blocksize will be produced.

- progressreport:  set do-query to False (default is True)
- checktimestamps:  set silent to True (default is False)

this will evolve into a proper subclass of gobject like gstadapter.  the
exported api is *NOT STABLE*

when first segment ends before start of requested interval, the clipping
would've done weird things.  this fixes it by removing such segments

Conflicts:

	python/lloidparts.py

a few bugs are fixed in this:

- a nofakedisconts was missing following the autochisq
- the block size wasn't being propogated into the framesrc
- some commented-out eye candy code wouldn't have worked (it still might not, but it should)
- etc.