Fixed an error caused by allowing multiple Search/Replace windows (fixes #127).
Fixed replacement logic in Find/Replace that could replace selected fragment (ref #127).
Added selecting text and Cmd-F shortcut in Find dialog on OSX (ref #127).
Added `nomousezoom` option to disable zoom with mouse wheel in the editor.
Fixed compatibility with wx2.8 (thanks to Samuel Dionne-Riel; closes #128).