[TIDOC-1490] 1.4.0 Release Notes

Conflicts:
	CHANGELOG.md
[TIDOC-1490] Address PR comments
[TIDOC-1490] Fix typo
Making headings consistent across all release notes.

Conflicts:
	CHANGELOG.md
[TIDOC-1490] Add Widget deprecation message
[TIDOC-1490] Fix headers
Merge pull request #434 from bhatfield/tidoc-1490-1_4_X

[TIDOC-1490](1_4_X) 1.4.0 Release Notes