[feature/revisions] Some basic clean up of the style. Still needs work.

PHPBB3-10755
[feature/revisions] Check permissions when viewing individual revisions.

PHPBB3-10755
[feature/revisions] Disable radio buttons if there's only one  revision left.

PHPBB3-10755
[feature/revisions] Move "Current Post" under revisions column.

- Adjust column widths.
- Adjust visibility of out-of-range rows.

PHPBB3-10755
[feature/revisions] Rename U_PROFILE as it conflicts with global var.

PHPBB3-10755
[feature/revisions] Do not allow wiki users to change "Wiki post" setting.

PHPBB3-10755
[feature/revisions] Allow non-moderators to specify reason for edit.

PHPBB3-10755
[feature/revisions] The "Wiki post" option is lost during preview.

PHPBB3-10755
Merge remote-tracking branch 'prototech/feature/revisions' into feature/revisions