.gitignore 'hsenv' related files
remove reference to deleted IsaMakefile
Update changelog, e-mails, and version bump to 0.7.0.0
Revert back version to 0.6.0.0

This is the version of the next release.
Add/update AUTHORS files
added pre-print of JCS'13 publication
moved publications to a more sensible place
more stable link to publications
update isar keywords for Isabelle2013