Added assertion to ensure inserted editor is not in the notebook already.
Fixed activating editor when starting the app on OSX (#327).
Removed focus handling workaround for editor tab changes (#89, #327).

The issue the workaround was for was already fixed in wxwidgets:
http://trac.wxwidgets.org/ticket/14142
Fixed restoring control focus when the app gets focus on OSX (fixes #327).
Fixed toolbar stealing focus after closing floating panels and dropdowns (#327).
Fixed some toolbar buttons being enabled with no editor tab open.
Fixed crash on OSX when changing focus while the app is being closed (#327).
Fixed focus on the editor after closing a dialog on OSX (fixes #328).
Added a workaround for focus switching between controls on OSX (#89, #327).

This is a more complete workaround for missing KILL_FOCUS event on OSX (an
incomplete workaround was removed by a315b1a8).
Fixed toolbar to stay shown after failure to start debugging.
Added `editor.wrapindentmode` and `editor.wrapstartindent` settings.
Upgraded metalua to v0.7.2.
Added centering of line after double click in the Output window.
Added double click navigation in the Output window for unnamed files.
Disabled message on failure to read symlinked folder content on Windows.
Added setting proper `arg[0]` value during debugging (fixes #329).
Fixed loading packages with dashes in filenames (fixes #330).

This still allows for `name-os-arch` format, but will load a package
if `os` or `arch` don't match any of the known values.
Added support to force local execution in console by prepending `!` (#326).
Fixed setting control focus when the main frame is hidden.
Updated auto-complete logic to use configured spec separators.