pass filter context to clover-check task.
ignore sub projects without clover dbs.
Merge pull request #36 from phasebash/coverage-filter

pass filter context to clover-check task.
Merge pull request #39 from phasebash/aggregate-db

ignore sub projects without clover dbs on aggregation. (Fix for Aggregation step on sub-module with no tests fails)
Updated documentation. Revert of pull request #39.
Updated version.