Fix #50: Ctrl+F highlights previous text

Opening the "find" or "replace" menu (Ctrl+F or Ctrl+H) highlights
any previous text in the textbox.  Undoes the solution to #44 since
it conflicts with this behavior.  The new behavior is consistent
with most other editors (e.g. Visual Studio).
Fix #51: Add word wrap support

A new option has been added that changes the default word wrap
setting (wrap or no wrap).  Individual documents can override the
default setting using the new "Word Wrap" checkbox in the "Edit"
menu.  Overrides are not saved between sessions.
Existing text highlighted for File Search
Fix #53: Added option to hide edit toolbar
Editors now save word wrap setting across sessions
Fix #19: Adds option to trim whitespace on save
Extend text fade-out timer to 2.5s from 1s
Bumped version number on plugins to x18
Fix #39: <pre> lines cut off in markdown
Fix only cleaning selection whitespace on save
Merge pull request #57 from Nik-U/master

Fix several small issues