Adding multinode harvester
Allow _content_type parameter
More defensive programming
Fix for null pointer in settings manager buildTree:

Fixes https://github.com/geonetwork/core-geonetwork/issues/681
Fix for css and less compilation.

It was found that the WRO4j importer doesn't handle /* ... */ comment blocks correctly and results in a corrupted css file after merging files with /*...*/ comment blocks.  This fix removes these blocks before performing the import to fix this issue.
Merge branch 'develop' of github.com:geonetwork/core-geonetwork into multinodeharvest

Conflicts:
	harvesters/src/main/java/org/fao/geonet/kernel/harvest/harvester/AbstractHarvester.java
Merging geonetwork 3.x harvester  into existing default geonetwork harvester
Merge pull request #674 from Delawen/multinodeharvest

Adding multinode harvester
Merge branch 'develop' of github.com:geonetwork/core-geonetwork into develop
If the file is created before this sentence (like on File.createTemp), we have to overwrite
Pool filesystems during testing to reduce the amount of memory used during testing.
Merge branch 'develop' of github.com:geonetwork/core-geonetwork into develop
Merge branch 'develop' of github.com:geonetwork/core-geonetwork into merge-path-develop

Conflicts:
	core/src/main/java/org/fao/geonet/kernel/setting/SettingManager.java
	core/src/test/java/org/fao/geonet/GeonetMockServletContext.java
	core/src/test/java/org/fao/geonet/GeonetTestFixture.java
	pom.xml
	web/pom.xml
	web/src/main/webapp/xsl/xml/harvesting/geonetwork.xsl
	wro4j/src/test/java/org/fao/geonet/wro4j/GeonetLessCssImportTest.java
	wro4j/src/test/java/org/fao/geonet/wro4j/GeonetWroModelFactoryTest.java