ENH: add ability to read html tables directly into DataFrames

use __import__ on 2.6

extra code from previous merges and importlib failure on tests

fix bs4 issues with no match provided

docstring storm!

markup slow tests (bank list data) and add tests for failing parameter values
PTF

ok that is really it for docstring mania

add testfor multiple matches
DOC: CONTRIBUTING.md, add link to discussion on plotting code conventions
DOC: update RELEASE.rst
Merge branch 'cpcloud_read_html'

* cpcloud_read_html:
  DOC: update RELEASE.rst
  ENH: add ability to read html tables directly into DataFrames