add ims files to gitignore
Extra parameters for master node

Expose build, launcher, listener to groovy scripts run on the master
node.

Exposing build should let groovy scripts do some more interesting things
such as adjusting variable values for later steps.
fix icon path
Merge branch 'master' of github.com:jenkinsci/scriptler-plugin
Merge branch 'enhancement-1' of https://github.com/rhadman/scriptler-plugin into rhadman-enhancement-1
expose 'build', 'listener' and launcher to script when executed on master
fix image references
[FIXED JENKINS-17259] don't throw exception in case Token can't be expanded