Merge pull request
#929 from juliantaylor/multiline-history...
Merge pull request
#929 from juliantaylor/multiline-history
some readline multiline-history fixes and tests
* fixes crash when readline is absent (#911)
* do not save input from e.g. raw_input in history
* do not add empty or duplicate entries lines to the history.
* add tests for _replace_rlhist_multiline
* protect pyreadline from some incorrect assumptions of equivalence to regular readline
closes gh-911