BUG/ENH: fixed NCDC formatting bug, added a function to make hourly xtab tables
BUG: NCDC exporter actually uses -col- kwarg now
TST: added NCDC export test and test files
WIP: tweaks to a couple of tests
MNT: cleaned up NCDC formatting
ENH: broke out some helper fxns and added 30-min intervals to resampler
ENH: added progress bar class and pep8 stuff
TST: updated known test values for NCDC exporter
ENH: added progress bar to downloads
Merge pull request #39 from phobson/ncdc-format-fixes

MNT: NCDC format fixes