Clean everything when calling 'scons -c'
Set correct base dir for lcov
Make destructor of Domain virtual

The destructor of a virtual base class should almost always be virtual.

see http://www.amazon.com/dp/0201924889 or
http://stackoverflow.com/questions/461203/when-to-use-virtual-destructors
Remove coverage files
Merge pull request #8 from Moredread/fix/virtual_destructor

Make destructor of Domain virtual
Merge pull request #6 from Moredread/issue-5

set correct base dir for lcov
Merge pull request #10 from Moredread/feature/clean_all

Clean everything when calling 'scons -c'
Merge pull request #11 from Moredread/feature/clean_coverage_temps

Remove coverage files