FIX change action variable source to getViewer

Previously we were using the request to get the action parameter. However for custom URL structures and nested controllers, this won't work and causes template selection to break.
BUG Load just one of each plugin.
Merge pull request #3040 from mateusz/plugins30

BUG Load just one of each plugin.
Test nested controller actions and Controller->getViewer

Adds tests and supporting classes for testing that the correct action is passed to Controller->getViewer inside Controller->handleRequest.
FIX: ConfirmedPasswordField used to expose existing hash
Merge pull request #3044 from mateusz/hash

FIX: ConfirmedPasswordField used to expose existing hash
API tinymce editor no longer transforms paragraphs with margin-left into blockquotes
This is legacy behaviour which does not often reflect the expected behaviour of the current editor. indent and outdent can (in some situations) prefer to use margin instead of padding. sapphiremce_cleanup faultily assumes that such indented text should be block quoted, and replaces this with a block quote element. This is not necessary, since the blockquote element can be placed explicitly by the user when necessary.

To replicate the incorrect indentation behaviour, configure tinymce to use the 'lists' plugin (via admin/_config.php) and attempt to indent some text. Indented text will be unexpectedly replaced with blockquotes.
remove leading tab

fix rendering
update 3-forms.md

adds the missing "/" in the url
Merge pull request #3062 from jimt/patch-1

remove leading tab
Oembed warning if GD function is missing

Silencing errors from a function is terrible so I've stopped that.

I've also added detection for if `imagecreatefromstring` is a declared function and a useful error is thrown if not
FIX Docs for DataList::filter()

The docs incorrectly stated that DataList::filter() needed escaped input, but this isn't true as the ExactMatch filter (and others) escape the values for you.

Anyone following that advice would have double escaped arguments
Merge pull request #3073 from dhensby/patch-5

FIX Docs for DataList::filter()
BUG Fix edge case IE8 / dev / ssl / download file crash
Prevents issue at http://support.microsoft.com/kb/323308 appearing on dev
Merge pull request #3069 from tractorcow/pulls/3.1-ie8-download-ssl-crash

BUG Fix edge case IE8 / dev / ssl / download file crash
Merge pull request #3067 from sanjaymundhra/patch-7

update 3-forms.md
API Make default gridfield paging configurable
Documentation improved
DOCS: Minor fixes to RestfulService documentation
Merge pull request #3026 from tractorcow/pulls/3.1-gridfield-paging

API Make default gridfield paging configurable
Fixed config setting link