pure refactoring (extracted two helper methods for constructing the noise pattern parts)
start of issue #19 added readProfessions in HDFSUtils to read in profession_train data
added method to write out profession count list (writeProfessions(String)) in HDFSUtils.java
#19 forgot to actually commit the changes, only commited the output file I had in the last commit
Merge remote-tracking branch 'origin/reading_training' into shlomo.merging.reading_training
#24: made readProfessions DRYer
#24: removed countLines(...) since readLines(...).size() would return the same
#24: renamed readProfessions(...) to getProfessionCounts(...) since the method is processing the file content. Also changed the writeProfessions(...) to writeProfessionCounts(...) and changed the key-value separating character to '\t' (tab) for easier reading in using the KeyValueTextInputFormat.
#30: changed HDFSUtils.readLines(...) to return a list of Strings - one for each line: better representation of a file which could contain duplicate lines, deduplication is not always required

Made getFilesCount independent of data source (takes in List<String>): better testable.

Removed HDFSUtils.writeProfessionCounts(...): following Pito's golden rule "don't optimize until you have to". getProfessionCounts(...) works in under 3 seconds with the original profession_test.txt. No need to write the counts into a file and read it in later.
#30: refactored the tests. Added getProfessionCounts(...) performance test.
The performance test shows that reading in the whole profession_train.txt with over 673k article -> professions assignments as well as parsing and counting - all in total - takes less than 5 seconds. Thus we don't need methods to write and read the counts into / from a separate file.
#30: added JUnit test for HDFSUtils.getProfessionCounts(...).
Closes #30.
#19: moved getProfessionCounts(...) into the new ProfessionUtils class: meanwhile it is independent of the data souce (HDFS vs. local file vs. hard coded List<String>), thus it has nothing to do with HDFSUtils.
Closes #19.
Merged master into branch