2.0-alpha2 release

We should do an alpha2 release now that the IP address stuff has stabilised.

Once we have that, we will be pretty much ready for the release. The only thing in our most recent roadmap (http://community.aegirproject.org/discuss/another-stab-short-and-long-te...) that are missing are:

• #1083366: Make the spokes authoritative for files/ and private/ directories
• #705026: Allow creation of example.com/foo and example.com/bar type of sites (Part I)
• #1920152: Docs missing about drush 5 on debian squeeze

Once we have those, we should probably have a beta1, but in the meantime, we are talking about an alpha2.

If no one else gets around to it, i'll do this somewhere next week.

Draft release notes:

This release features improvements to the IP management mechanisms that were broken in the last alpha1 release. We now manage IP addresses individually, and check if an IP is in use before allowing it to be deleted.

We also finally leave the files alone on spokes in the multi-server model, a long-standing bug in the 1.x series that led to data loss. A lot of work was done to standardize the Nginx configuration to allow for simpler, yet optional, configurations that leave the admin in charge of choosing the optimisation methods. This is still work in progress, tracked in #1635596: nginx: do not decide the policy for users.

List of issues addressed:

API changes:

* deprecate hosting_ip_delete_revision(), dupe of hosting_ip_delete() now that revisions are gone (8 weeks ago)
* allow running tasks that appear to be running with --force
* remove deprecated DEBUG flag in debian package
* #1785624: Some Drupal API changes in D7 (and D8) are not used/respected properly
* #1945950: Rename provision_drupal_sync_site_back()
* #1083366: Make the spokes authoritative for files/ and private/ directories
* #1812338: Refactor sync back
* a new control file has been introduced in /etc/nginx/basic_nginx.conf to force the nginx configuration to be the "simpler" one (see #1635596: nginx: do not decide the policy for users)

New features:

* #1929372: Flag tasks with logged warnings
* #1515416: On a package page, show table listing sites and platforms using the package
* #1853620: Add db_name to site summary
* #1681904: Ability to configure a url to redirect to in site configuration.
* #1968226: manage each IP individually on the server level - manage IPs individually
* add uninstall command
* Nginx Security: BEAST attack protection and fix for PCI compliance.

Bugfixes:
* #1930670: Duplicate entry 0 for key PRIMARY in hosting_ip_addresses when installing / upgrading
* #1907028: user warning: Table 'XXX.hosting_ip_addresses' doesn't exist
* #1961920: nginx: [emerg] invalid number of arguments in "limit_conn_zone" directive in /etc/nginx/conf.d/aegir.conf
* #1923490: Incorrect error message in aegir-provision2.preinst
* #1901508: "gzip --rsyncable" is invalid on OS X
* #1678528: Database deleted on edge cases
* #1930740: provision-delete leaves a drushrc.php lying around
* Nginx: Do not override Nginx name with fake Apache name.

Other:
* #1923552: Rename 'Queue runner settings' tab to 'Queue daemon'
* #1834036: Add 'hosting platform pathauto' to the .gitignore
* #1785624: Some Drupal API changes in D7 (and D8) are not used/respected properly
* #1979496: Update upgrade.sh.txt for Drush 5
* #1974752: Document old_uri option for provision-deploy