build directory support

[Christian Thalinger <twisti at complang dot tuwien dot ac dot at>]

Hi!

I've just commited a bunch of patches to add the missing Uses tags for
various packages.  This is a preparation for the real patch that adds
build directory support.

I decided to implement/fix this because I didn't want to copy a handfull
of Mauve sources around to test it, but rather use one checkout on a NFS
share.

Currently it works very well (locally) and the Harness only compiles
sources when there is no corresponding classfile or the sourcefile is
newer than the classfile (inner classes are not checked).

There's only one problem left: different files some tests depend on.
Some testlets, like
gnu/testlet/java/beans/SimpleBeanInfo/loadImage.java, require the file
to be relative to the classfile location, so we need a way to copy these
files to the build directory.

On IRC I talked to Mark and Andrew and we concluded that a new tag would
be the best solution.  Like:

// Files: testImage1.gif

This tag would then copy the file from the source directory to the build
directory, if it does not already exist.

I'd like to commit my changes ASAP because I'm not sure I can find all
broken testlets.

- twisti