Fixes build breaking in recent rake versions
Adds support for specifying an explicit private IP in VPC mode
Added tests for the private-ip-address option
Bump to 0.6.3 for development
[KNIFE-190] VPC Private IP support

Merge branch 'tomdz/vpc-private-ip-support'
Added options to allocation and assign EIPs after launch.
[KNIFE-151] Remove associate_new_ip feature.

Code review determined that the allocation of new IPs is out of scope
for this tool, thus I have removed to to facilitate merging this.
Merge branch 'ssd/KNIFE-151'
Merge branch 'master' of git://github.com/opscode/knife-ec2