ec2rotatehosts: add --instance argument

allows replacement of single host without relying on ASG order
add check to warn when no hosts to rotate
instance being rotated no longer counted in ELB healthy checks, which allows
data nodes to be upgraded (ie: decommission, rotate, join, terminate)
Merge pull request #36 from WrathOfChris/cm-rotatesingle

ec2rotatehosts: add --instance argument
add handling for 'all' to map to -1 for allowing all traffic
Merge pull request #37 from WrathOfChris/cm-allow-alltraffic

add handling for 'all' to map to -1 for allowing all traffic
cloudcaster multi-group support

- attaches list of security group IDs to LC / interface
- also updates ec2createapp to also attach list
Switch all shebangs to #!/usr/bin/env python
multi-group support for cloudcaster

- fix an iteration in early code committed before testing
- only post a secgrp once to the list of security groups
Merge pull request #35 from yo61/feature/fix_aws_env_ps1

Remove setting of PS1 from awsenv.
Should never really have committed awsenv in its original form :)
Merge pull request #40 from yo61/feature/rb_gh39_fix_shebang

Feature/rb gh39 fix shebang.
thx robin.
Merge pull request #38 from WrathOfChris/cm-cloudcaster-multigroup

cloudcaster multi-group support.

new app.groups list parameter that allows additional multiple security groups to be added to an instance.