Fix focus issue with 2012 Search / Replace Control

Visual Studio 2012 moved the Search / Replace control to an editor
adornment and gave it incremental searching capability.  Yet they didn't
implement IIncrementalSearch hence we had to query specially for this
adornment to prevent VsVim from stealing keystrokes

closes #1073
Allow spaces around the = in 'let' expressions

This gets us part of the way to fixing #1074