Fix #130: Fix false-positive in ReturnNullSniff

Fix #147: Undefined array index when a function is after a class

Prepare changelog for 1.2.0

Merge pull request #125 from bmitch/changelog

update changelog

Merge pull request #122 from bmitch/cleanup

Clean up code

Merge pull request #101 from bmitch/add72

Add PHP 7.2 to Travis-CI build

Merge pull request #95 from bmitch/bmitchell-#90

Fixes #90

Merge pull request #94 from bmitch/bmitchell-#67

Fixes #67

Merge pull request #87 from bmitch/bmitchell-#86

Fixes #86