proper text and binary handling in iris client

closes #831, closes #799
Accounting floating point precision in AuxPlane

closes #735
Trying to autodetect dtype for writeWave

closes #791
typo in 5c92797099357cdad62f5516e6808b347529c244
testing: avoid failing tests when imgur fails SSL certificate
verification during upload (see e.g.
https://travis-ci.org/obspy/obspy/jobs/29074482#L841)