can classes
test canning classes
py3compat for class canning
remove non-functional View.kill method

This method cannot be implemented until engines have local nannies
that can send signals.

closes #2772
Merge pull request #2755 from minrk/canclass

can interactively defined classes

*Only* interactively defined classes are canned.

closes #2754
P3K: fix DeprecationWarning under Python 3.x (base64.encodestring is deprecated)
Merge pull request #2776 from minrk/rmkill

remove non-functional View.kill method
Merge pull request #2778 from kmike/p3k-deprecations

P3K: fix DeprecationWarning under Python 3.x 
Allow the %run magic with '-b' to specify a file.

The syntax would be:
    %run -d -b file2.py:30 file1.py

to break at line 30 of file2.py when running file1.py.

The old syntax
    %run -d -b 20 file1.py
still works the way it used to.

Suggested by user gozzilli on StackOverflow
(http://stackoverflow.com/questions/14305203/ipython-set-a-breakpoint-in-imported-file/).
Fix bp_file -> filename
Merge pull request #2782 from ellbur/run-breakpoints

Allow the %run magic with '-b' to specify a file.