Adding the ability to filter check results by start time.

Defaults: all check results since 1970, at most 100 results
Added 'get_actions' method to retrieve list of Pingdom actions.
Added get_summary_average
ignore .idea files
add initial sphinx docs
move documentation to docs dir, sphinx documentation
ignore _build dir
consolidate license to license file
consolidate license to license file
consolidate license to LICENSE file
pep8
pep8
pep8
pep8
remove unused imports
pep8
modified project to use requests
add requests as dependency in docs
more doc cleanup
add excludes filter