Object inspect & diff: Quote property names that require it.
Fixed typos in error messages.
Improve the appearance of hex dumps.
Changed inspect to use JavaScript syntax for binary arrays.
Postprocess hex diffs to make sure that spaces between hex chars don't get rendered with a background, and that the same chars are marked in the ASCII dump.

Fixes #69.
Fixed jshint problems.
utils.diffStrings: Take an options object and make it configurable whether to highlight special characters.
Use the "control pictures" unicode chars to represent bytes < 0x20 in hex dumps.