Updates internal links

Links within pages pointed to page anchors (e.g. '#timeline'), a legacy of when these pages were joined together into a single page. This change updates these links with the correct urls.
Miscellaneous copy improvements
Adds 'process' page to 'platform' section
Adds 'back to help center' button to help page layout
Merge pull request #12 from newavenue/help-reorganization

Help reorganization