PHP 5.4 as a requirement

git-svn-id: http://www.pimcore.org/svn/pimcore/private/core/trunk@3886 1f8fe7d8-47f0-464c-8d0a-336f4953ab05
asset download: save memory, use readfile

git-svn-id: http://www.pimcore.org/svn/pimcore/private/core/trunk@3887 1f8fe7d8-47f0-464c-8d0a-336f4953ab05
build auto version (2961) ...

git-svn-id: http://www.pimcore.org/svn/pimcore/private/core/trunk@3888 1f8fe7d8-47f0-464c-8d0a-336f4953ab05