Update quick start with clone instructions for git

Signed-off-by: Jody Garnett <jody.garnett@gmail.com>
Merge branch 'master' of github.com:jive/geoserver

Conflicts:
	doc/en/developer/source/quickstart/index.rst
Merge branch 'master' of github.com:geoserver/geoserver
Merge branch 'master' of github.com:geoserver/geoserver
Merge branch 'master' of github.com:geoserver/geoserver
GEOS-5279
Improved IM filter junit tests
updating SCM location; add lin/win instructions
Copyediting GeoWebCache sections
tweaked logging null app context case, from severe to warning
logging data directory at INFO, and added setter for catalog
added constructor taking a GeoServerDataDirectory instance directly
updated constructors to take catalog interface, rather than impl
added flag to turn off extended validation, needed for system test setup
safely disposing a resource from its cache, and fixing issue not closing file stream when loading schema.xml/xsd file
handling case during cascade delete of a resource not having any layers that reference it
fixing issue not closing file stream
factored out directory removal, and made null safe
fixing issue not checking for non-existance of workspaces directory
updated how id for service and settings objects are handled, also ensured collections resolved