Optionally specify encoding of JCAMP file
Optionally specify encoding of JCAMP file

Allow to specify an encoding for reading JCAMP files. Keep the current
behaviour by choosing the default encoding if no encoding is specified.
Use io.open() to read a JCAMP file to guarantee backwards compatibility
with Python 2.

kaustubhmote/nmrglue,jjhelmus/nmrglue,kaustubhmote/nmrglue,jjhelmus/nmrglue