Fix HTMLText AbsoluteLinks not parsing placeholder

Add an AbsoluteLinks method to HTMLText that parses placeholders instead of returning the raw value.
Fixing FormField not setting readonly attribute on setReadonly(true)
Upload: refactor file versioning
Fix: WYSIWYG now returns valid HTML in tables

The WYSIWYG by default creates invalid HTML5. Creating a table and running it through W3C validator returns the following error: The border attribute on the table element is obsolete. Use CSS instead.
BUG Fix grid field showing search without search component added
ref: CWPBUG-133
added in a getter
Update dataobject.md

There's no way to make things like [api:DataObject->beforeUpdateCMSFields()] work, is there? 

I removed those kind of api tags (the links yielded a 404 page), and corrected a few other link-rendering issues.
Update modeladmin.md

Corrected many broken link-renderings. Also removed the "Related" link to [genericviews Module](http://silverstripe.org/generic-views-module) because it doesn't work, and I can't it elswhere.
Update i18n.md

Fix a link being inside backticks, which broke the formatting.
Merge pull request #3171 from ss23/patch-4

Update i18n.md
Update datamodel.md

Fix broken link to SS_List->column
Merge pull request #3172 from stevie-mayhew/patch-1

Update datamodel.md
Update for Mink 1.6 compatibility
Update modeladmin.md

DataList is immutable, so need to assign.
DOCS Explicitly exclude dev deps for deployment

Docs should tell users how to deploy without development dependencies
API New JS sprintf and inject replacement functions

Fix sprintf issues when replacement was at start of string + introduce
new inject function using injection map similar to the PHP version of
_t()
Update Form.php

tiny typo
Merge pull request #3193 from phillprice/patch-3

Update Form.php
BUG Sanitise the PHP output.
Merge pull request #3196 from mateusz/patch-html-editor-field

BUG Sanitise the PHP output.