Added Maven section
maven edits and wordsmithing
updated maven with more settings and instructions - author codyhoag
Maven edits up to "Using Liferay Maven artifacts"
Edit new Maven content in Plugins SDK chapter
Insert Maven chapter into Dev Guide
Maven section minor edits
Update header IDs for Maven and Device dev guide sections
Maven - adjust heading levels, table formats, and a header ID
Merge pull request #392 from jhinkey/maven-dg-6.1.x

Maven chapter 6.1.x