[CDF-292] - TextInputComponent lifecycle: postchange is trigger twice
  - Validate if the value has changed to trigger Dashboards.processChange() only when necessary
  - Removed keyup event of TextareaInputComponent, Dashboards.processChange() is only triggered on change event
  - Added sample for TextAreaInputComponent
Merge pull request #252 from afrjorge/CDF-292

[CDF-292] - TextInputComponent lifecycle: postchange is trigger twice