Docs. CLOUDSTACK-1152. Restore second half of paragraph which was deleted in error.
Docs. Change software version number in book title pages to 4.1.
Docs. Fix broken hyperlink.
Docs. Fix broken hyperlink to Creating Network Offerings. Add the section to the book, and add conditional cross-references so it will build in either book (admin or install). This section was already in the repo, but was not previously included in any book. Also removes stray reference to obsolete software version number 3.0.3 in the Creating Network Offerings section.
Docs. Remove redundant inclusion of add-security-group.xml, which was breaking the docs build.