mySQL implementation

 * A mySQL module for the eyeConfig library.

See http://wiki.oneye-project.org/development:mysql for technical details
Finalise mySQL implementation pre-pull request

 * Set a numerical primary key in tblUser
 * Correct the name of the used constant in system.xml conf file
 * Remove a stray error_log()
Update userConfig-test branch

 * Includes new mySQL module

As before, this branch is not to be used on production systems and is not to be merged with Master