Add loadJars() to load a directory of JARs

A lot of applications have code like the following to load all JARs from a given directory into the class path. Should we provide it out of the box and if yes, in what module?

/**
 * Loads all .jar files placed in the `jars` directory of SqlStore
 */
var loadJars = exports.loadJars = function() {
    // add all jar files in jars directory to classpath
    var dir = module.resolve("../../../jars/");
    var repo = getRepository(dir);
    var list = repo.getResources().filter(function(r) {
        return strings.endsWith(r.name, ".jar");
    });
    list.forEach(function(file) {
        addToClasspath(file);
    });
};

[botic]

Pull request: #425

I decided to go with loadJars(), since it takes a repository (or path treated as one) and looks for matching resource names. addToClasspath() is already blocked by the global function.

[botic]

So I see three options:

1. adding a addJarsToClasspath(dir) to the global object. But this is broken by design, since we should never ever add anything to global again.
2. add addJarsToClasspath(dir) in the engine module, like Manfred proposed. But then we should also add the standard addToClasspath(path) to the engine module, which would be a non-global alternative to addToClasspath(). The global variant would stay as legacy code, the engine alternatives would be the way to go.
3. Drop this issue and keep copying this snipped.