Add nodebrew 0.9.7

Remove package/python.rb, outdated binary package

Add vpnc package

Update openconnect from 7.06-1 to 7.08

Update subversion to 1.9.7 and correct the install method of serf

Update stunnel to 5.42

update libxml2.rb to avoid compile error later

Change aircrack_ng to make it configure itself correctly.

Update heroku from 4.28.3 to 6.13.9