Minor fix.  Will require 3.1 when it is released
Change default content type to text/html, so that browser traces will work
Improvements to FilePathResult

- Fix issue where sometimes not all bytes are written to response
- Added documentation
- Added mime-type guessing based on fileName extension

(And documentation+formatting changes for FileResult)
More improvements and clarifications to FileResult / FilePathResult
Version bump
Make currentUser settable, so we can have "switch to user" functionality

Made sure to note in the docs that this is something you should only
expose in a secure area of your site...
Small bug fix to error handler (would only show up on async platforms)

Also updated the docs
Added "MDS" (Month-Day-Short) to thx Dates.  Eg Dec 25
More consistent behaviour with HttpRequest's queryString and postString

Also added it to documentation.  Always give "" if nothing.  Before
it was sometimes null etc, or worse, "null" (a 4-character string
saying "null")
Better error handling and general cleanup.

Includes:

- Faking error positions for last known modules
- Error handlers are always given an HttpError, not a Dynamic exception
- Better tracking of async execution for debugging where a request is up to, last active module etc
- When -debug is defined and an error is caught in DispatchHandler, it logs where it was caught (in the executeAction() or executeResult() stages)
- The ErrorPageHandler now has 2 dynamic functions, one for the error content, one for the page layout.  This makes it easier to swap the layout for a site