added composer.phar and dev-dependencies from ci-tasks

Hello,

since we want to test what we develop we should provide the developer with the required environment.
This adds the composer.phar and the dev-dependencies like phing, phpunit, etc.

Also the changes in build.xml allow to use `-Dmysqlrootpass=''` if the root user has no password. 

I would have preferred not to set the dependencies under version control, but you actually have to own a github accout to successful install all dependencies, so its no option to leave this job to jenkins.

This is more of a suggestion than a must have, although it would help to integrate unittests in our workflow. All comments are appreciated.

Greetings from Leipzig University Library,
Ulf Seltmann