add cf-release v147 thru v149
use env var to code where cf-release dir is
initial v149 template attempt
refactor latest_cf_release_version to allow sed to change it
update expected latest version to v149
fix remaining specs broken from adding new release
document commands to automate adding new release [fixes #264]
add required nats.machines for v149
Document about updating new templates for requirements
medium size uses 0.core for nats
bump v0.7.6 - v149 support
Merge pull request #265 from cloudfoundry-community/support-v149

Support v149