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.
workarounds for ETHZ FDSN node
more workarounds for ETHZ FDSN WADL differences
More fault tolerant parsing of the WADLs.

This should enable the parsing of most WADLs even if they are not fully
conforming to the standard.
Changes to WADL parser.

I tried to come up with some logic that should make it possible to parse
a large variety of WADL files with slight deviations.
Special case handling for missing gain information.

It also now adds the instrument sensitivity as stage 0.
test cases for parsing parameters from all real world application.wadls currently served out there
Some more unit mappings.