Hide singleton instance of barcode factory from user.
Merge branch 'master' of github.com:jimevins/glbarcode

Conflicts:
	app/main.cpp
	doc/pages/implementing-1d-barcodes.dox
	doc/pages/usage.dox
	examples/generate-samples.cpp
	examples/usage-example-1.cpp
	glbarcode/Factory.cpp
	glbarcode/Factory.h
	glbarcode/capi/gbc_factory.cpp
	test/test-datamatrix.cpp
	test/test-debug-renderer.cpp
	test/test-svg-renderer.cpp