clear In[] prompt numbers on "Clear All Output"
For more version-control-friendly `.ipynb` files, this strips the `In[]` prompt numbers when doing a "Clear all output". This reduces the amount of noise in commit-to-commit diffs that would otherwise show the (highly variable) prompt number changes.
* 2.1.7 (earliest dep) will simply not work, so skip it
* 2.1.9-10 log the interrupts, so add a short delay to ensure the log
messages don't come after the prompt.
rename plaintext cell -> raw cell
Raw cells should be *untransformed* when writing various output formats, as the point of them is to let users pass through IPython to their rendered document format (rst, latex, etc.). This is different from what is the logical meaning of 'plaintext', which would suggest that the contents should be preserved as unformatted plaintext (e.g. in a `<pre>` tag, or literal block).
In the UI, these cells will be displayed as 'Raw Text'.
WARNING: any existing v3 notebooks which use plaintext cells, when read in by versions after this merge, will silently rename those cells to 'raw'. But if such a notebook is uploaded into a pre-merge IPython, cells labeled as 'raw' will simply *not be displayed*.
small changes in response to pyflakes pass
Only significant change: removes incomplete kernelstarter file, which shouldn't have been in the repo at all.
closes#1499
clear_output improvements, which allow things like progress bars and other simple animations to work well in the notebook.
* `clear_output()` clears the line, even in terminal IPython, the QtConsole and plain Python as well, by printing `\r` to streams.
* `clear_output()` avoids the flicker in the notebook by adding a delay, and firing immediately upon the next actual display message.
* `display_javascript` hides its `output_area` element, so using display to run a bunch of javascript doesn't result in ever-growing vertical space.
This reduces flicker during common loops like:
for step in stuff:
clear_output()
print something
the timeout is flushed *immediately* on any subsequent output.
ensures that config loading matches what would happen in ipcluster.
The only change needed in IPClusterStart itself was moving the on_stop registration from init_launchers to start_controller, where it should have been anyway.
