Help doesn't check for duplicate sef-urls when saving documents

(from [621da506ccf671f6e1257a0824b6c4960cc5ae99]) Help doesn't check for duplicate sef-urls when saving documents. Also reverts to correct makeHelpLink method. [#211 Help doesn't check for duplicate sef-urls when saving documents state:resolved] https://github.com/exponentcms/exponent-cms/commit/621da506ccf671f6...

(from [feb862b9d4bb132a54ce22c654e4559c1343c8f4]) Fixes Help doesn't create or check for duplicate sef-urls when saving documents. Also fixes a number of issues with multiple help versions in the system. Adds/fixes selecting Help Section for each Help Doc. Now manages help item/doc location_data AND section # to allow moving items to different help sections. Though it's not perfect with broken help data tables (section set to 0 or missing location_data), it won't choke and can update bad help docs to have correct location_data and/or section entries. [#166 Feature request - add a help module show and/or change assoc module/location_... state:resolved][#211 Help doesn't check for duplicate sef-urls when saving documents state:resolved] https://github.com/exponentcms/exponent-cms/commit/feb862b9d4bb132a...