Validate notNull directory argument in addRepository
Merge pull request #3 from aslakknutsen/patch-1

Validate notNull directory argument in addRepository
Add tests to verify method argument validation
Merge pull request #4 from aslakknutsen/validation_test

Add tests to verify method argument validation
Add option to register Custom AddonRepository implementations
Merge pull request #5 from aslakknutsen/custom_repository

Add option to register Custom AddonRepository implementations
AddonManager now avoids updating SNAPSHOT dependencies
FORGE-1260: Upgraded to Maven 3.1.1
FORGE-1260: Upgraded to Maven 3.1.1 (missing arquillian)
Performance optimizations
Added proxy type caching to reduce CPU and object instantiation overhead
Implemented proxy and Imported instance caching.