Improve documentation and casting types
Summary: Fix type mismatches between docblocks and signatures.
Test Plan:
$ phan | grep PhanTypeMismatchDeclaredParam $ phan | grep PhanTypeMismatchDeclaredReturn $ phan | grep PhanTypeMismatchProperty $ phan | grep PhanTypeMismatchArgument $ phan | grep PhanCommentParamOnEmptyParamList
Reviewers: dereckson
Reviewed By: dereckson
Differential Revision: https://devcentral.nasqueron.org/D1066