search result submission does not clear line properly

[ivanov]

the right line gets submitted, but it doesn't display nicely.

For example, here was me reverse searching for import rl and then hitting <enter>

$ ipython
Python 3.5.2 (default, Sep 28 2016, 18:08:09)
Type "copyright", "credits" or "license" for more information.

IPython 5.4.0.dev -- An enhanced Interactive Python.
?         -> Introduction and overview of IPython's features.
%quickref -> Quick reference.
help      -> Python's own help system.
object?   -> Details about 'object', use 'object??' for extra details.

In [1]: -i-search)`import rl': import rlipython

In [2]:

[ivanov]

looks like this has to do with the invisible characters we're printing to have nice colorful In [] prompts. IPython 4 used a prompt_manager to handle this tomfoolery - accounting for the number of invisible characters on render. I guess as part of getting #6 and #9, I might as well resurrect the prompt_manager stuff here.

[ivanov]

Oh, figured it out, needed \001 and \002 escapes for readline to know about those pesky invisible escape codes.