Improved / corrected REST documentation (see GEOS-5595)

Conflicts:

	doc/en/user/source/restconfig/rest-config-api.rst
	doc/en/user/source/restconfig/rest-config-examples/rest-config-examples-curl.rst
User Manual SLD Reference - fixed Halo syntax
User Manual Filter reference - added boolean Literal
using direct reference to Catalog to avoid startup race condition
ensuring intermediate checkouts of geotools/geowebcache checked out into build, and ignored so not added on commit and tag