Added default parallel environment to 'crg' executor
Upgraded version number and build timestamp
Changed assertion in 'singleItemOrList' method
Fixed issue in TextFileCollector empty condition
Upgrade to Groovy 2.3.8
Refactored grid executors in order to support job directives in launcher script
Added BSC specific executor
Fixed bug that prevents a job is added to the polling queue when submit operation fails
Code clean
Updating build timestamp and version numbers
Refactored 'sge' and 'crg' executors so that qsub directives are provided 
on top of job wrapper script