Info about getting set up using composer and MAMP

Added by request of Gábor Novoszádi from community feedback and thanks to the gist from @kkirsche. I have supplied a link to the gist as it is well written, with permission we may look to rework for direct inclusion at some point :)
Docs / Tests for Director::absoluteURL
Merge pull request #3011 from tractorcow/pulls/absurl

Docs / Tests for Director::absoluteURL
Prevent IE errors on hidden login forms

In order to focus a field, it needs to be visible,
which can't be guaranteed on a core level by the login form JavaScript.
Optionally check for visibility via jQuery if it exists,
and allow explicit disabling of this behaviour via a unique identifier.
Add 3.0.10 upgrade docs
Merge pull request #3010 from camfindlay/patch-3

Info about getting set up using composer and MAMP
FIX - missing link url for composer

My bad, have amended this.
Merge pull request #3014 from camfindlay/patch-4

FIX - missing link url for composer
Delete formatted images after image upload

This change fixes an issue where old/existing formatted images are used
when a filename is reused (by overwrite or by coincidence), regardless
of if the file contents have changed. To users this mainly manifests
as a file overwrite appearing not to work; the thumbnails in the CMS
show the original image until regeneration is forced.

Calling Image::deleteFormattedImages() after image upload ensures that
no stagnant formatted images will be used.
Merge remote-tracking branch 'composer/3.0.10' into 3.1.4
3.1.4 upgrading docs
BUG Fix Date and SS_DateTime::FormatFromSettings
This issue is caused by the odd default behaviour of Zend_Date, which attempts to parse yyyy-mm-dd format date and times as though they were yyyy-dd-mm.
Update upgrading docs 3.1.4
Merge remote-tracking branch 'origin/3.0' into 3.1
Merge remote-tracking branch 'origin/3.1.4' into 3.1
Merge pull request #3013 from silverstripe-iterators/pulls/login-form-js

Prevent IE errors on hidden login forms
Fixed reference to the templates documentation
Merge pull request #3023 from camfindlay/patch-5

Fixed reference to the templates documentation
Returning response from doChangePassword()
Merge pull request #3024 from silverstripe-iterators/pulls/changepw-return

Returning response from doChangePassword()