Scalameter for java code

Please note that I've worked on version forked from http://axel22.github.com/scalameter/.
Also, I have a NullPointerException at the end of regression tests, even with scala code coming from HTMLReporter.scala at line 167. I have not been able to determine if it comes from my code, or my computer...
Same here - `Measurer` is now a top-level class, so Java clients can refer to it directly.

    package org.scalameter.japi
    object Measurer {
      def get = org.scalameter.Measurer
    }

We then need to add the factory method to the `Measurer` companion object, for each measurer implementation:

    def default = ...
    def memoryFootprint = ...
    // etc.

Java clients then write:

    Measurer.get.default

This design is more maintainable as it does not require ScalaMeter devs to add a new Java wrapper each time a new measurer/aggregator/warmer implementation is added.