Added placeholder content to test a two-page Table of Contents
Removed unnecessary parindent command.
Precontent header has same style as content header.
If twoside, clear doublepage after cover.

The added extra page does not have any page numbering.
Alter page numbering and chaptermark on odd/even pages.
Indentation fixes.
Document cleanup, onesided layout by default.
Merge branch 'feature/twoside' into develop

* feature/twoside:
  Document cleanup, onesided layout by default.
  Indentation fixes.
  Alter page numbering and chaptermark on odd/even pages.
  If twoside, clear doublepage after cover.
  Precontent header has same style as content header.
  Removed unnecessary parindent command.
  Added placeholder content to test a two-page Table of Contents