TDD: Starting to add unit testing, tested the Length class.
TDD: changing the assert parameters order to match the jUnit convention
TDD: Added tests for the Area class
Tests: Added test's for MathUtil and Altitude classes.
Update README.md
Merge branch 'master' into TDD

Conflicts:
	DroidPlanner/src/org/droidplanner/helpers/units/Area.java
Merge pull request #646 from arthurbenemann/TDD

Test Driven Development