Several small improvements
- Replace existing output file in HistoryUtils.downloadFileFromUrl.
- Moved the GALAXY_INSTANCE_URL field from ConcatenateExample to BaseExample.
- Minor change to log message in GalaxyWorkflow.parseJson.
Added support for workflow parameters
- Added RandomLinesExample: this workflow has two steps with identical parameters (modified from a blend4j test).
- Modified HistogramExample to use parameters and workflow engine configuration.
- The WorkflowEngine.runWorkflow method now returns whether it ran successfully.
- GalaxyWorkflowEngine: removed expected output length checking and use dataset name for output file keys.
Refactored GalaxyWorkflowEngine.runWorkflow
- GalaxyWorkflowEngine: refactored the runWorkflow and related methods.
- Fixed some Checkstyle issues.
Merge remote-tracking branch 'trait/master'

Conflicts:
	src/main/java/nl/vumc/biomedbridges/core/Constants.java
	src/main/java/nl/vumc/biomedbridges/core/Workflow.java
	src/main/java/nl/vumc/biomedbridges/core/WorkflowEngine.java
	src/main/java/nl/vumc/biomedbridges/examples/BaseExample.java
	src/main/java/nl/vumc/biomedbridges/examples/ConcatenateExample.java
	src/main/java/nl/vumc/biomedbridges/examples/HistogramExample.java
	src/main/java/nl/vumc/biomedbridges/galaxy/GalaxyWorkflow.java
	src/main/java/nl/vumc/biomedbridges/galaxy/GalaxyWorkflowEngine.java
	src/main/java/nl/vumc/biomedbridges/molgenis/MolgenisWorkflowEngine.java