LRDOCS-391, wordsmithing on site templates and page templates sections of User Guide, also fixed some typos
Clarified introduction to site templates section of User Guide
LRDOCS-391 Added details to site templates section of User Guide, replaced organization site with site in example
Applied consistent formatting to the section titles of User Guide chapter 3
LRDOCS-391 Added section outlined what actions are allowed/disallowed for site administrators and site template administrations for sites set up to propagate changes from a site template
LRDOCS-391 Updated User Guide section on propagating changes from sites templates to sites; discussed how importing portlet preferences and portlet data works
Merge pull request #437 from jrao/LRDOCS-391

https://issues.liferay.com/browse/LRDOCS-391