Two issues fixed

I fixed two small issues: when reopening the tabs, Asciidoc is now shown again (before, the tabs were not loaded, and you had to reopen the file). Also changed the tab sequence, and renamed the tab to Preview, which is probably a better description than AsciiDoc, since in reality, the edit tab is AsciiDoc, and the output is just HTML. So 'Preview' would be better.

Also, when releasing this plugin, don't compile it using JDK 1.7, but use JDK 1.6, otherwise it gives issues on a lot of IntelliJ/other products (there is already an issue for that).