Modified documents for version 0.5.0 (#256).
Modified copyright year on source header (#256).
Modified pom.xml version (#278).
Supports extra compiler plugin directories (#281).
Merge remote-tracking branch 'private/issue/256-M9' into 0.5-develop
Merge remote-tracking branch 'private/issue/256-M9-license' into 0.5-develop
Merge remote-tracking branch 'private/issue/278-M9' into 0.5-develop
Merge remote-tracking branch 'private/issue/281' into 0.5-develop