experimental use of HTML5DownloadFileSave

alpha code - fallback handling for saveFile() using link to data: URI.
Still not creating 100% correct content, but it's getting there...
more experiments with 'download saving'

this time: get document.documentElement.outerHTML as soon as main() is
invoked (but before startup makes changes to the DOM, such as adding
backstage, adding <applet> for JavaSaver, etc.
more 'download saving'

still has problems:
HTML entities encoded/decoded
applet elements added
download detection (FF20 issue?)
fallback for manual 'save link as'
comment out download saving until TW280
update version/date for TW272beta1
limit IE fixup for PRE newlines to ieVersion < 10

IE 9- uses \r for hard newlines in PRE blocks
IE 10+ uses \n standard
handling for FileReader in backstage>import

Import.js: get file object from "browse" control and save in context
FileAdaptor.js: pass context.file object as XHR 'options' param
Http.js: refactored ajaxReq and added localAjax to handle FileReader
with fallback for loadFile and/or local jQuery Ajax handling.
code cleanup in localAjax() handler
use //# commenting for 'download saving' code

commented out until TW280
remove debugging alerts and fallback code
Merge branch 'master' of https://github.com/ericshulman/tiddlywiki into ericshulman-master

Conflicts:
	js/Version.js