Update PluginRegistry.java

Merge pull request #277 from makiam/improve-layout-import-menu

Merge pull request #276 from makiam/separate-renderers-instances

Merge pull request #274 from makiam/fix-layout-deregister

Merge pull request #275 from makiam/rollback-pm-theming-support

Merge pull request #270 from makiam/pm-mirror-dialog

Merge pull request #264 from makiam/green-robot-leak-fix

Merge pull request #267 from makiam/exta-test-for-object-info

Merge pull request #269 from makiam/drop-pm-theme-declaration

Merge pull request #266 from makiam/clean-xstream-deps