add note about submodules & opal compatibility
upgrade to 1.5.0.preview.2 plus a few commits
upgrade to Asciidoctor HEAD; fix footnoteref in example
update asciidoctor.js in dist
switch to 1.5.0.preview.5, patch version number
Merge pull request #18 from anthonny/master

Make Asciidoctor.js available to Bower
Merge pull request #19 from mojavelinux/asciidoctor-1.5

upgrade to 1.5.0.preview.5
Update bower to 1.5.0-preview.5
Merge pull request #30 from anthonny/1.5.0-preview.5

Update bower.json to 1.5.0-preview.5
upgrade Opal; remove opal-sprockets, update bower metadata

- upgrade Opal to 0.6.2
- upgrade Asciidoctor to 1.5.0.preview.6 to get Opal compatibility fixes
- declare bower dependency on Opal 0.6.2
- update bower metadata
update dist files