Add comment to view templates with version in source, last changed date

Description

Implement the ability to add comments to view templates, with information such as version in source and when it changed last time. Use this format for the comment.

FORMAT = Version: A.B.C.D. Modified: yyyyMMdd  (always use 4 segments for version string, even it is zero - Version: 4.6.0.0)
SAMPLE = Version: 4.1.2.3. Modified: 20170531

As a result, developers can easily compare versions with a quick look. Remember to add comments to the release note or readme about templates changes. It is as important as breaking changes.