notebookapp: add missing whitespace to warnings
add IPython.get_ipython

library entry point for get_ipython

does not rely on injection into globals
Don't rely on `get_ipython` in builtins in library code
don't use deprecated ipapi.get

It's been deprecated for three releases.  Come on guys.
remove reference to nonexistent 0.14 in deprecation warning
move core.ipapi -> core.getipython
remove deprecated `get`
Strip prompts even if the prompt isn't present on the first line.

Users (including me) often copy and paste examples from just after the first
prompt. This checks for prompts in the first two lines of a block, but if they
aren't found there, it will ignore prompt-like prefixes in later lines, to
minimise interference with multi-line strings etc.

Closes gh-3206
Merge pull request #3323 from takluyver/strip-prompts

Strip prompts even if the prompt isn't present on the first line.

Users (including me) often copy and paste examples from just after the first prompt. This checks for prompts in the first two lines of a block, but if they aren't found there, it will ignore prompt-like prefixes in later lines, to minimise interference with multi-line strings etc.

This fixes both incoming copies (transformed before running code) and outgoing (copied from the Qt console).

Closes #3206
Merge pull request #3333 from t-8ch/patch-1

notebookapp: add missing whitespace to warnings
Merge pull request #3286 from minrk/get_ipython

don't use `get_ipython` from builtins in library code

mainly adds IPython.get_ipython() as a library-level handle that does the same thing.