Some seed files don't have any encoding set - write() function was failing.  This should address those issues
Fixed help in chop, removed semicolons in streams, fixed streams write doesn't fail when there is no encoding in the traces
Now looking for encoding in the mseed attribute - why didn't this blow up before?
Merge pull request #6 from mhearne-usgs/filter_fixes

Some seed files don't have any encoding set - write() function was faili...