fdsn: set "str" as default type for "eventid" parameter (as specified by
FDSN official documentation)
mseed parsing errors are printed.

Proper warnings are raised when an error is encountered during the
reading of a MiniSEED file. In this case we raise a warning to be able
to at least read the parts of the file up to the error.

Conflicts:
	obspy/mseed/core.py
changelog
Better error message for full SEED files.
Removing extra space
PEP8