note absence of autoloader for local extensions

Added tip noting the absence of an autoloader for local extensions. This is noted in the howto for local extensions, but was not mentioned in these getting started instructions. (And the existence of the howto was not obvious either.)
Add viewless contenttype option

The viewless option mentioned in the Resource Contenttype howto was absent from this listing. Added description of this option and link to the howto to make this list more complete.
Merge pull request #133 from dpfavand/master

Note absence of autoloader for local extensions