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
Merge pull request #3076 from martinduparc/patch-4

Fixed config setting link
BUG Fix ImageTest
Image test would erroneously reset the Image::$backend to null if the test was skipped, breaking subsequent test cases
Merge pull request #3068 from kinglozzer/patch-1

DOCS: Minor fixes to RestfulService documentation
Removed demo folder
BUG Fix jstree when duplicating subtrees
Merge pull request #3031 from tractorcow/pulls/3.1-fix-tree-duplication

BUG Fix jstree when duplicating subtrees
Merge pull request #3078 from tractorcow/pulls/3.1-remove-thirdparty-demo

Removed demo folder