refactoring
allow gzip compression in external sort
fix memory profiling info
refactor ExternalSortingInputLoader
increase default memory amount allowed for external sort
Merge branch 'master' of https://github.com/mifeet/cr-batch

Conflicts:
	sources/src/test/java/cz/cuni/mff/odcleanstore/fusiontool/ODCSFusionToolExecutorRunnerIntegrationTest.java
updated readme
Merge branch 'master'

Conflicts:
	sources/src/main/java/cz/cuni/mff/odcleanstore/fusiontool/loaders/ExternalSortingInputLoader.java