Updates change notes.
Release 1.2
Reads environment variables using Groovy style.
Reads signing password from DCR_SIGNING_PASSWORD environment variable.
Reads Sonatype (Maven repository) credentials from environment
variables.
Extracts M2_HOME check into function.
Checks if SNAP_BRANCH is 'master' before uploading archives.
Merge pull request #52 from damage-control/release-1.2

Release 1.2