`mvn clean` does not clean native components

[basil]

Invoking mvn clean removes the target/ directory but not the native components. It should somehow invoke build.cmd clean in a similar fashion to how the normal build invokes build.cmd build.

[basil]

CC @pbo-linaro

[pbo-linaro]

Thanks for the report.
This is something we can happily fix after merging #112.

[basil]

This is not blocked on #112. The regression was introduced in #116 and should be fixed independently of #112.