[INTERNAL] sap.f.DynamicPageTitle - private _stateChange event introduced
[INTERNAL] sap.f.DynamicPageTitle - private _stateChange event introduced

This change implements an event, allowing apps to react to the title
switching states (from collapsed to expanded and vice-versa).
Initially the event will be private.

Change-Id: I15ac43074d1d62e8cb0f712bdfa8529c16711522

cschuff/openui5,SAP/openui5,SQCLabs/openui5,SQCLabs/openui5,cschuff/openui5,SAP/openui5,nzamani/openui5,nzamani/openui5,SAP/openui5,SQCLabs/openui5,SAP/openui5,nzamani/openui5,cschuff/openui5