BUG Allow PHPUnit installation with composer / Fix travis
Merge pull request #3090 from tractorcow/pulls/2.4-phpunit

BUG Allow PHPUnit installation with composer / Fix travis
Removed php5.2 incompatible syntax
Merge pull request #3099 from tractorcow/pulls/2.4-php52fix

BUG Removed php5.2 incompatible syntax
MINOR Use composer @stable for PHPUnit

Using stable will allow some packages to be downloaded as zips instead of clones all the time.
FIX Opt-out pf form message escaping (fixes #2796)

This fixes a limitation introduced through http://www.silverstripe.org/ss-2013-008-xss-in-numericfield-validation/.
Form messages used to accept HTML, now they’re escaped by default, effectively removing the ability
to pass in HTML and take care of escaping manually.

We pass through HTML to message in core through the CTF system, so this needs to be fixed.
It’s an alternative fix to https://github.com/silverstripe/silverstripe-framework/pull/2803.