build.xml: added convenience build-start, build-debug, rebuild-start, rebuild-debug
build.xml: added convenience build-start, build-debug, rebuild-start, rebuild-debug

These represent the most common developer operations. Imported from a helper script
as they belong here.

ilscipio/scipio-erp,ilscipio/scipio-erp,ilscipio/scipio-erp,ilscipio/scipio-erp,ilscipio/scipio-erp