Add listener.ssl_certificate_id support to AWS ELB
health_check is an optional parameter for ELBs
allow vpc_zone_identifier in aws_autoscaling_group
add MapPublicIpOnLaunch
config: `module` structures parse
config: validate no duplicate modules
config: Append works with modules
config: Merge for modules works
Drop the extra sudo calls
Install all required packages at once
Also install pkg-config and libpcre3-dev so Go does not complain
Make apt-get silent
Write directly to /etc/profile.d/gopath.sh instead of /tmp
Drop the execute permissions
Unify GOPATH capitalization, delete empty line
Update comment, build Go if cd succeeds
Drop the SRCROOT variable
Consistent ordering of arguments for apt-get commands
Merge pull request #291 from ivuk/vagrantfile-changes

Vagrantfile changes
config/module: start, lots of initial work