add lxml to the list of install dependencies
add parameter_code filter to nwis.hdf.get_site_data
handle kbdi dataframes more efficiently
use concat with a list comp rather than an append loop and merge fips codes with
pandas.merge
simplify _as_data_dict
change value names: kbdi_avg -> avg; kbdi_min -> min; kbdi_max -> max
in docstring: fips -> FIPS
added tests
fix tests
minor formatting
Merge branch 'hdf5-read-params' of git://github.com/dharhas/ulmo into hdf5-read-params
move nwis.hdf5.get_site_data parameter_code kwarg before path, complevel and complib
bump version to 0.6.0-dev since we now have backwards incompatible changes
make version number string available at ulmo.__version__; closes #56