#972 Checkstyle: check proper JavaDoc @param/@return/etc sentence end.

• Best to review per commit.
• Checkstyle: check several JavaDoc tags with user-entered descriptions for having proper ends of their last sentences:
  • Check @deprecated (if followed by message), @implNote, @implSpec, @param, @return and @throws.
  • Support single line and wrapped descriptions.
  • Allow ending with ., ?, ! and a tag (like <ul>...</ul>).
• Fixed all violations. Also small other JavaDoc fixes.
• I checked the time it takes in the development environment to do a full clean and rebuild. It was 1m4s-1m7s in develop and 1m5s-1m6s in this branch. So, it doesn't noticeably seem to impact the build performance.

Closes #972 (closed)