sort: allow arbitary attributes
attach response information to example stream
more flexibility in Response.get_evalresp_response

- possibility to specify choice of output units ("VEL", "ACC", "DISP")
  as supported by evalresp
- possibility to specify start/stop stages for deconvolution
Trace: new deconvolve() method (logic based on simulate() with less
cluttered options) to remove instrument response based on
new Response object introduced with obspy.station
Added support for gain only blockettes
Gain only stage now works for the response calculation.
New context manager to catch the output.

This variant does not leak file descriptors.
Nested with does not work with Python 2.6.
Merge pull request #698 from obspy/catchoutput_cm

New context manager to catch the output.
Merge branch 'master' into station2
Small changes to the unit handling
station: correctly read/write ResponseStages that only have StageGain
and nothing else (also adapt full random test to have one of those
minimal ResponseStages)
Sort all blockettes for one channel by the blockette number.

This should fix an issue with misordered SEED files.
Now sorting by stage sequence number and a custom blockette order.
Merge pull request #700 from obspy/resp_blkt_ordering

Ordering blockettes when RESP files are written.
correct version info when writing RESP files
Added FIR stage handling
Blockette 59 has no stage sequence number. Will always end up at the
end.
Fixing waveform_id parameter in obspy.core.event.FocalMechanism
to list of WaveformStreamID as specified in QuakeML docs (fixes #633)

no deprecation handling as I can't find any QuakeML example containing
this parameter - for now I assume this has not been used yet - if someone
needs a deprecation handling feel free to submit a pull request

also small fix for obspy.pde - @claudiodsf please review
updating docs