Extract common xjc and runtime code to external 'core' jar. To allow xjs usage without jaxb-runtime.
JAXB is split by modules: core, xjc, runtime, jxc.
XJC module requres some JAXB runtime implementation on classpath!
Looks good overall, however too many dependencies went to core and thus jaxb-impl would depend on twice as much than before. I think we should create separate jaxb-jxc jar so that removing the jaxb-xjc dependencies from core is allowed.
full splitted project without 'tools'