added basic eddn functionality w/ hdf5 caching
filter dataframe with start:end before returning
add init file
add decoding ability and parsers for some twdb gw instruments
remove cruft
added test for rows of data and fixes to core
add tests for message timestamp and first test twdb_stevens parser
make sure tests aren't hitting cached data
correct sutron example
add dual channel stevens test: WIP
working stevens dual channel test
added working tests for 3 formats that should cover all the twdb groundwater wells
tweak stevens formatter
try and deal with missing data generically
make hdf5 cache optional with use_cache parameter, fix tests
add doc strings
convert print statements to use logging module
remove unused imports
Merge pull request #67 from dharhas/usgs-eddn

Add USGS EDDN service to Ulmo.