Use map from test case name to test case function

[asqasq]

CrailBenchmark and HdfsIOBenchmark should use a map from testnames (command line) to test case functions (see PR 35).

Example: [...] int locationClass = 0; boolean useBuffered = true;

	String benchmarkTypes = "write|writeAsync|readSequential|readRandom|readSequentialAsync|readMultiStream|"
			+ "createFile|createFileAsync|createMultiFile|getKey|getFile|getFileAsync|getMultiFile"
			+ "getMultiFileAsync|enumerateDir|browseDir|"
			+ "writeInt|readInt|seekInt|readMultiStreamInt|printLocationclass";
	Option typeOption = Option.builder("t").desc("type of experiment [" + benchmarkTypes + "]").hasArg().build();
	Option fileOption = Option.builder("f").desc("filename").hasArg().build();

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