Bug 508772 - [simrel] Even further simplification of build.xml

It is very simple, now. Works from 'tools', as well as if "copied up" to
'build' as well as from IDE. This was done
by assume BUILD_HOME is "one level up" from directory of build.xml.

Also added lots more documentation in build.xml about targets and
properties. 

Change-Id: Ie2e868c7108d55e12d715ecca6def4f97f922300
Signed-off-by: David Williams <david_williams@acm.org>
5 files changed