Fix Open With Browser action.

Originally the Mylyn action to open a task with the Browser was failing
because the constant used to compose the HTTP URL was wrong
("/issues/show/"). Now the value is correct ("/issues/") and the Mylyn
action works as expected.
Merge pull request #6 from giamma/openWithBrowserFix

Fix "Open with browser" action.
Updated README

- added buildhive build badge
- added link to download ZIP with built plugin as P2 repo
- removed 'scary' info about one time rewrite in master due bad merge
Merge pull request #8 from ljader/update-readme

Updated README
Remove duplicate entry in feature.xml dependencies
Merge pull request #10 from nfalco79/fix_dupe_import_slf4j

Remove duplicate entry in feature.xml dependencies