Integrating release candidate for libmseed 2.8

* just removed the static msr_unpack_data redeclaration of
  obspy-readbuffer.c. Did not use the new msr_parse_selection()
  jet
mseed: add msr_parse_selection to windows def file
Rolling out final libmseed 2.8 released

* download url: https://seiscode.iris.washington.edu/attachments/download/97/libmseed-2.8.tar.gz
Adding msr_parse_selection to mseed win def file
Merge pull request #496 from mbyt/libmseed-2.8

Libmseed 2.8