style: cheshire3.resultSet made PEP8 compliant
bugfix: typo numrecs -> numReq
bugfix: bug when readline is absent (closes issue #53)

 * added readline to requirements.txt
 * gracefully degrade console UX in absence of readline
style: made cheshire3.resultSetStore PEP8 compliant
docs: additional documentation in cheshire3.baseObject (API)
docs: improved docs in cheshire3.resultSet
Merge branch 'develop' into feature/unittests1.1
tests: added tests for ResultSet serialization
bugfix: SimpleResultSet serialization bug fixed

Fixed bug when serializing SimpleResultSet attributes with None values.
tests: added unittests for ResultSetStores
bugfix: missing expiresReverse file for BdbResultSetStore
tests: fixed bugs in cheshire3.tests.testResultSetStore

- Return value for create_resultSet is an identifier, not the ResultSet

- ResultSet _should_ be altered by storing - gains ``id`` attribute
  test modified accordingly