rename bundle to archive throughout (mechanical change)
rename bundle to charm; rename receiver variables
rename Archive to CharmArchive etc
gofmt
rename Read to ReadCharm
Merge remote-tracking branch 'origin/master' into bundledata

Conflicts:
	charmdir.go
rename import paths
Merge branch 'rename-bundle-to-archive' of github.com:rogpeppe/charm into rename-bundle-to-archive
Merge pull request #8 from rogpeppe/rename-bundle-to-archive

charm: prepare for adding bundle support
charm: add BundleData, parser and Verify method.
add some more tests and comments as per review
Merge pull request #9 from rogpeppe/bundledata

charm: add BundleData, parser and Verify method.
charm: fix build.Import path
Merge pull request #10 from rogpeppe/001-fix-testing-charm-path

charm: fix build.Import path