EclipseHelper: the class loader *can* be the system class loader...

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
EclipseHelper: Eclipse puts a file:/.../dir/ as first class path entry

... so skip EclipseHelper if it is not...

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Merge branch 'eclipse-helper' into HEAD

Some fixes to the EclipseHelper noticed while debugging ij-ops.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>