* Updated change log for 5.4.0-preview
* Updated 5.4.0 preview to add two new feature requests
* Modified change log as per review
* Modified the wordings
* Updated readme, changelog, and install instructions
* Updated instructions and sample test for 5.3.0 RTW
* Fixed sample code to adhere to php coding standard
* Fixed cases and spaces
* Modified NOTE for UB 18.04 based on review comments
* Added 'exit'
* Modified change log and readme based on review to PR 811
* Applied review comments
