Fix HTMLText AbsoluteLinks not parsing placeholder

Add an AbsoluteLinks method to HTMLText that parses placeholders instead of returning the raw value.
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a table and running it through W3C validator returns the following error: The border attribute on the table element is obsolete.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.
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
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 i18n.php

Norwegian should use 'nb' and not 'no' in common languages array
Merge pull request #3231 from tscole/patch-2

Update i18n.php
Fix: Incorrect calculation of UploadField height (fixes #2862)
Fix: Remove superfluous iframe resize for UploadField (fixes #2863)
FIX declarations matching PHPUnit_Framework_Assert

FIX for phpunit error message: ERROR [Strict Notice]: Declaration of SapphireTest::assertNotContains() should be compatible with PHPUnit_Framework_Assert::assertNotContains, and the same error for assertContains()
FIX Add support for compositedbfield within many_many_extraFields

Previously selectFromTable would simply try to select the composite field name. This expands the extraField name to include the children field names and uses CompositeDBField::writeToManipulation to generate the correct SQL for the queries.
Remove PHP 5.6 from allowed failures

PHP5.6 is due for release rather soon, so we should be ready for it
BUG using isDev or isTest query string no longer triggers basic auth
BUG: Fix incorrect common_languages config
Merge pull request #3255 from tractorcow/pulls/3.1/fix-i8n-locale

BUG: Fix incorrect common_languages config