Added code to get statistics from langlink matches

* New classes added - matching langlinks using hashmaps and stats on the
* output data;
* Unit test updated - test file added with some manually written matches
* to test if these are contained in the program output;
* Wiki homepage updated;
* Code runnable on sk->hu and sk->en matches, does the reverse linking at
* the same time;
* Stats run on the generated output data and write into a new file the
* missing pairs (those that are in sk->en but not in en->sk, or vice versa)