Add README.md and test results.

README.md

+# Tugas Map Reduce
+Aidil Rezjki S S - 13517070
+## How to Build & Run
+Scripts are available in `Makefile`. You can use `make` to run the available commands.
+## Word Counter
+[Word Counter Test](images/word-counter-test.png)
+## Average Counter
+[Average Counter Test](images/average-counter-test.png)
+## Top Ten Filter
+[Top Ten Filter Test](images/top-ten-filter-test.png)