LRDOCS-798 Applied title-casing to section titles
LRDOCS-798 Added basic information about the Activities portlet, listed the other core Liferay social portlets
LRDOCS-798 Added explanation of how to use the Activities portlet and core Liferay portlets, added screenshot of the Activities portlet
LRDOCS-672 LRDOCS-502 Explained how to use the Alerts and Announcements portlets, explained how to configure custom delivery notification settings, added screenshots
LRDOCS-798 Updated link to Liferay's Javadocs to point specifically at Liferay the social API
Merge pull request #686 from jrao/LRDOCS-798

https://issues.liferay.com/browse/LRDOCS-798