draw paths in stretches of 100 points to avoid the severe decrease in performance that may occur if long paths are draw
Added modifier key event handling for the macosx backend and cleaned up key event handler.
Updated to not use NSDictionary literals for pre-obj2.0 compiler support.
Removed shift from modifier flags as the character returned already includes shift operation
Merge pull request #1816 from mdehoon/master

Avoid macosx backend slowdown; issue 1563
Merge pull request #1841 from cimarronm/macosx+modifiers

Fixes issue #1259 - Added modifier key handling for macosx backend
Fixes #1862: The PS backend would inadvertently close file handles passed to it on Python 3.  The TextIOWrapper that handles the encoding from unicode to ascii needs to be detached before its destructor is called, otherwise it will call close on the underlying file object.  Also cleans up how with statements are handled to avoid the sometimes problematic null contextmanager.
Merge pull request #1862 from mdboom/ps-file-closing

Matplotlib savefig() closes BytesIO object when saving in postscript format
fix the pyplot version of rc_context

Before this, when using the rc_context dangling from pyplot, one would
get an AttributeError for ``__exit__``, because plt.rc_context wasn't
actually returning anything before this change.
Merge pull request #1866 from ivanov/fix-rc_context

fix the pyplot version of rc_context