Merge pull request #1198 from silverstripe-rebelalliance/open8231

ENHANCEMENT: fixed styling bug with the text in the file upload drop are...
Fixed TreeDropdownField loading indicators
Require Config.php in core to avoid fatal errors when building manifest
Don't fail TinyMCE cleanup if no current instance is set

Bug has been observed in IE8
Merge pull request #1315 from dhensby/patch-4

FIX Adding preview method to CsvBulkLoader
FIX "Insert Link" and other TinyMCE loading bugs (fixes #8327)

Caused by SS loading a URL with html entities (&amp;)
through the Requirements API, which only works when directly
inserted into the HTML template (standard behaviour),
but garbles the URL GET parameters when loaded via the jQuery.ondemand
JavaScript/XHR logic.

It didn't fail the request, just meant that tiny_mce_gzip.php wasn't
getting all the required options from the GET parameters.
And since this newly loaded file contains the same JS globals,
it would override previously loaded (correct) state.
Merge remote-tracking branch 'origin/3.0' into 3.1

Conflicts:
	admin/javascript/LeftAndMain.js
ENHANCEMENT Additional image generation functions now self-determine if a modification to the underlying image backend is necessary before generating additional image files.
IX Load _config.php's after static config manifest

This allows more sophisticated handling of config alterations
in _config.php. One example is additions to DataObject::$db
based on configuration which requires some processing.

See https://github.com/unclecheese/TranslatableDataObject/blob/master/TranslatableDataObject.php
Merge pull request #1317 from chillu/pulls/config.php-after-statics

FIX Load _config.php's after static config manifest
Removed internal/outdated/speculative docs from requirements.md
Merge pull request #1312 from chillu/pulls/deprecation-docs

Deprecation docs
FIX ConfigStaticManifest persisting access level after parsing a static
FIX Incorrect parsing of T_STRING values in class spec parsing

* Due to missing break, the T_STRING case would fall through to array.
* The values were being added to the wrong variable.
* Added missing support for missing null values.
Merge pull request #1322 from ajshort/pulls/class-spec-parsing

FIX Incorrect parsing of T_STRING values in class spec parsing
Merge pull request #1321 from silverstripe-rebelalliance/feature/config

FIX ConfigStaticManifest persisting access level after parsing a static
Missing closing <a> tag in installer
BUG Database config values aren't escaped

Causes minor UI issues if you try use database configuration values that happen to have " or other values in them.
Merge pull request #1326 from ss23/patch-1

Missing closing <a> tag in installer
Merge pull request #1327 from ss23/patch-2

BUG Database config values aren't escaped