Just use $JAVA_HOME instead of '$JAVA_HOME'. Fixes build breaker in at
least bean on Linux.

only testContent and the ods range name test remain in-build, everything
else is now a subsequenttest
if needed the subsequent_filters-test can be moved to an in-build test
in Module_sc.mk

this is not perfect but better than loading the file several times while
we should only call read-only methods

Sorry for the large unstructured commit. But hey, the Android code is
experimental so far.

Extract the native lo-bootstrap code into a fairly normal library
built in sal. (Previously it was the JNI part of the "Bootstrap" app.)
Just linkink normally to liblo-bootstrap from C++ code that uses it
works fine, no need to do a dlsym lookup.

Bootstrap is still a subclass of NativeActivity and can thus still be
used as an "app" (to start unit tests, or whatever), but can also be
used from some other app's Java code to just get access to the
lo-bootstrap native methods.

Introduce a new top-level "module", android, for Bootstrap and the
experiments with DocumentLoader.

Note that the experimental DocumentLoader app still crashes. It can't
create the com.sun.star.frame.Desktop instance.

I spent lots of time debugging in the painfully inadequate
ndk-gdb. (Even the newer gdb build from the "mingw-and-ndk" project is
quite crappy in many ways.) I should really experiment with
corresponding code on a normal platform first before even trying on
Android. Basically, I think that if I just can get the concept of Java
code that instantiates and uses LO components *in-process* working on
a normal desktop platform, it should work on Android, too.

potential improvements: only load the file once and use fods instead of
ods