Merge tag 'v1.2.1'

1.2.1

 * slt-release-start: fetch origin before branching (Sam Roberts)
slt-release: change -n to -p, so `-up` updates

It should be easier to remember the options like this.
Merge pull request #14 from strongloop/mnemonic-options

slt-release: change -n to -p, so `-up` updates
Fixup README with install and release usage
v1.3.0
Merge branch 'release/1.3.0' into production