Add ant-based code coverage support to Android SDK

Add ant-based code coverage support to Android SDK

Target 'run-tests' launches all the unit tests against the tested project.
Target 'coverage' emma-instruments the tested project's classes,
runs the tests against instrumented classes, collects code coverage data
and extracts it to human-readable form as report.html.
android_test_rules.xml contain additional rules for test projects.
Test projects are auto-recognized by presence of the tested.project.dir
property, which will be auto-generated for tests projects. Temporarily,
please add this property manually to the build.properties file.
Current version is mainly tested with default, android generated test projects.
This version includes also fixing relative to absolute paths for
properties which are most likely to be changed by user in external
property file.