update utils.py for py3 and backwards-compatible with py2#61

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geomars wants to merge 2 commits intoimwilsonxu:masterfrom geomars:master

+2-2

Commits on Oct 4, 2017

change from flask_wtf.html5 to wtforms.fields.html5 due to FlaskWTFDeprecation Warning
geomars
committed
add support for py3 and backwards-compatible with py2.6 and 2.7 for the raise syntax
geomars
committed