LRDOCS-863 Initial updates for 6.1 Dev Guide
LRDOCS-863: Added event-listing-portlet instructions
LRDOCS-863: Remove event listing instructions from service builder and reference to IDE section
LRDOCS-863: Update snapshots for Liferay IDE 2.0
LRDOCS-863: Wordsmithing and typos
LRDOCS-863: Minor changes for Plugins SDK chapter
LRDOCS-864: Update Maven section for Lifereay IDE 2.0
LRDOCS-864: Update Maven section snapshot for IDE
LRDOCS-864: Image re-numbering and typos
LRDOCS-863: Update portlet instructions for IDE 2.0
LRDOCS-868: Update Themes for Liferay IDE 2.0
LRDOCS-868: Update Layout template section for IDE 2.0
LRDOCS-863: Correct snapshots to display 6.1 SDK and runtime
LRDOCS-863: Update Themes chapter for IDE 2.0
LRDOCS-879: Update Ext section for Liferay IDE 2.0
LRDOCS-864: Edit Maven chapter nesting
LRDOCS-863 Move  the default portlet cleanout into the section on creating plugins.
LRDOCS-863 Creating plugins section promoted to level 2 header and given header ID
LRDOCS-863 Replace the example project/plugin specifications from the Service Builder section with references to the project/plugin creation sections of the IDE chapter.
LRDOCS-863 & 864 Add header IDs