More updates.. Yeah, maybe went a little crazy with this one.. What do you think about setting the defaults? Where would you like those set?

  - Hide/show the preview window.
  - Enable save to disk.
  - Specify a custom save location.
  - Added some default values for the settings dialog (MarkdownOptions), but they seem to be ignored.
  - Exposed MarkdownSharp options in the settings dialog:
    - AutoHyperlink
    - LinkEmails
    - AutoNewLines
    - EmptyElementSuffix
    - EncodeProblemUrlCharacters
    - StrictBoldItalic
- CoffeeScript
  - Added property to enable/disable the compiler.
  - Added property for custom save location.
- LESS
  - Added property to enable/disable the compiler.
  - Updated property for custom save location (hopefully won't conflict with existing settings now).
  - Added missing LessSourceMaps property to ProjectSettingsStore; I'm assuming it should be there with the others.
- Greatly cleaned up the MarginBase.GetCompiledFileName() code by using the ProjectHelpers.GetRootFolder() method. Thanks to @SLaks.
- Got the compilers (LESS, CoffeeScript, and Markdown) working when there isn't a project loaded and you're just editing one of the files.
- Upped the version to 1.3.13; I don't know if you want that incremented or not. (Sure makes it easier than un-installing everytime.)
- TODO Need to figure out how to set defaults, because right now the LESS and CoffeeScript compilers are defaulting to disabled..