Updated requirements to account for all supported versions of Python/Django
Fixed issue in previous commit that omitted syncdb/migrate instructions for Django < 1.7
Made Ubuntu/OSX instructions consistent and changed to follow best practices
PROJECT_PATH => BASE_DIR in keeping with current Django conventions
Corrected CMS_MAX_PAGE_PUBLISH_REVERSIONS default
Fixed links to use HTTPS for sites that now use it by default and updated html5lib's project page url