Initial commit of the Sanitizer code

This sanitizes html fragments inside wikitext if they come from another
space
Updates to the installation documentation

Tweaked and added a few things given my experiences with installing it
Updates to the installation documentation

Tweaked and added a few things given my experiences with installing it
Merge branch 'docchanges' of github.com:colmjude/tiddlyspace into docchanges

Conflicts:
	doc/CONTRIBUTING
Make is to friendly_uri can handle PATH_INFO on it

This basically means that http://tiddlyspace.com/foobar loads foobar,
and http://tiddlyspace.com/foobar/baz does too.

This _only_ works on friendly_uris.
Github is redirecting raw copies of files, so we must add -L to curls.
Revert "Github is redirecting raw copies of files, so we must add -L to curls."

This reverts commit 16ca3ed5f1ed2a77871e833376272c6051895791.
github is redirecting raw files from repos, curl must have -L
Remove a comment that is no longer true.

determine_space does tell spaces that are mapped,
Add experimental support for space-based css and javascript overrides in HTML representations.

If HtmlCss or HtmlJavascript tiddlers exist in the current space's recipes
then:

* the css link in the base template becomes a link to HtmlCss, instead
  of profile.css
* a <script> tag is added, pointing to HtmlJavascript

HtmlCss needs to be type: text/css
HtmlJavascript needs to be type: text/javascript

This provides the simplest solution to customizing the output of the HTML
representations. Some things to keep in mind:

* the existence of HtmlCss makes it be the _only_ css file. If
  profile.css is desired to be around, it should be @import-ed in HtmlCss
* If these tiddlers exist they are added to every html representation:
  tiddler, tiddlers, bag, bags, recipe, recipes and /profiles/<user>.
  This means that both CSS and Javascript needs to have some intelligence
  about what gets "turned on". You can't just assume one is on a
  friendly_uri page.

This puts a larger responsibility on the customizer, but it means that
the server side is simultaneously simple, flexible and powerful.
release 1.0.15

* experimental support for HtmlCss and HtmlJavascript tiddlers to
  control the HTML representations
Merge branch 'master' into clientSideSanitization
Added a .meta file for the Sanitizer code and added to the recipe

I've added it to the system-plugins recipe as that's where the following
code lives.
wrap 'thing' in container

all things should be wrapped in a container to allow theme designers
to do things such as center the tiddler/bag in the middle of the page.
move javascript to the bottom of the page

this has performance benefits
see http://developer.yahoo.com/performance/rules.html#js_bottom

it also is more useful for writing javascript as you don't have to worry
so much about the document being ready
Merge pull request #670 from bengillies/clientSideSanitization

Client side sanitization
Merge pull request #671 from jdlrobson/TemplateSuggestions

Template suggestions
Merge pull request #667 from colmjude/docchanges

Updates to the installation documentation
release 1.0.16

* use the latest alpha tiddlywiki (2.6.3.A8)
* use the client side sanitization plugin when including tiddlers
* adjust templates to be a bit better for customization
Display the original error message when giving a 404.

Otherwise we have no way of knowing what went wrong.