toolbar: use CustomEvent rather than DataContainerEvent

(integrated from trunk branch change 8b8d295 by Todd Whiteman <toddw@activestate.com>)
panes: tweak to event initialization

(integrated from trunk branch change 27885da by Todd Whiteman <toddw@activestate.com>)
bookmarks: use CustomEvent rather than DataContainerEvent

(integrated from trunk branch change bc77b0d by Todd Whiteman <toddw@activestate.com>)
panes: update comment (no functional change)

(integrated from trunk branch change 0929fd8 by Todd Whiteman <toddw@activestate.com>)
codeintel completions: use CustomEvent rather than DataContainerEvent

(integrated from trunk branch change 0cd64fe by Todd Whiteman <toddw@activestate.com>)
utils: kointegrate: rename back to original name