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.
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.
Added FIR stage handling
Blockette 59 has no stage sequence number. Will always end up at the
end.
Special case handling for missing gain information.

It also now adds the instrument sensitivity as stage 0.
Some more unit mappings.
Disabling the scaling from ObsPy as it appears to not be needed.
Less strict parsing.
fill in fdsn URL mappings dynamically in docstring
Implemented IIR coefficients response.
add deconvolve() to Stream