Initial commit.
XML parsing first try
Merge branch 'master' of ssh://bitbucket.org/aitjcize/ipc2581
Add .gitignore.
Add spec file.
complete basic architecture
complete ODB file system
StepRef, LayerRef, BomRef
Merge branch 'master' of bitbucket.org:aitjcize/ipc2581

Conflicts:
	.gitignore
add odb spec
TODO:need to initialize standard primitive
complete standard primitive
remove Sp- prefix
rewrite PolyStep as class
complete dictionaryUser (skip <Text>)
complete <Content>, though some skipped
complete CadHeader, skipped Spec, SurfaceFinish, and ChangeRec
complete <Layer> and <Stackup> architecture (not implemented yet)
complete <Layer> and <Stackup> in <CadData>
complete <Datum>, <Profile>, and <Package>, of <Step>