- don't need to list cyrus-sasl in our .spec file

- was causing TypeError to be raised due to wrong return value from .execute() handler
- while we're at it, this can be simplified quite a bit

- watch for input buffers whose offsets are negative with respect to output buffer
- note that earlier patch that claimed to make this change forgot to include the change

- motivated by high rate of spurious discont flags caused by 1 ns offsets among input buffers
- output timestamp is now computed from sample count
- pad properties are synchronized to each pad's own input buffer's timestamp, not the output buffers (which we now don't compute until the output buffer has been prepared)
- an extra assert is added to watch for input buffer offsets that are negative relative to output buffer

- had build time dep, but not runtime dep

- the buliding and packaging of the GIR files isn't working, this might fix it.

- note:  this patches some elements that haven't been ported yet

- don't call function with invalid timestamp

- remove reference to python elements and to interleave plugin
- update name of gstreamer python bindings RPM
- don't source gstenvironment.sh in .spec
- bump minimum required gstlal and gstlal-ugly for ER9

- comment out headers associated with not-yet-ported elements

- but disable all python elements

- still broken, but need ER9 release

- was harmless, but leading to puzzling warning messages

- was being printed out after what it was describing, and was probably meant to be printed only if --verbose is set (like other messages produced by this code)

- ensure pipeline is in READY state before calling this function

- also add a comment describing the current state of seeking logic, why it
  is that we have to seek pipelines the way that we're doing it.