Add test case for swft:import-jpeg.
Add test case for swft:import-png().
Add test case for swft:import-png where the PNG has an alpha channel.
Improve test of swft:import-png.
Improve test case for swft:import-png where the PNG has an alpha channel.
Improve swft:import-jpeg test case to also check the output structure.
Improve import-png and import-png-with-alpha test cases to check that base 64 encoded data is placed in the correct element.
Add test case for swft:import-jpega().
Improve all swft tests to check attributes.
Merge branch 'master'

Conflicts:
	.gitignore
	configure.ac
	test/Makefile.am
Rename test/swft to test/transform-and-verify.
Add missing EXTRA_DIST files.
Merge branch 'some-swft-test-cases'