LRDOCS-733 Updated User Guide's Marketplace chapter through the Finding Apps section
LRDOCS-733 Finished updating Marketplace section of User Guide's chapter on Marketplace and Plugin Management; updated all Marketplace screenshots
LRDOCS-733 Updated the Plugin Management section of the User Guide's chapter on Liferay Marketplace and Plugin Management; updated screenshots and removed obsolete sections and screenshots covering the old Plugins Installer; add new sections on the App Manager
Merge pull request #638 from jrao/LRDOCS-733

http://issues.liferay.com/browse/LRDOCS-733