Added metadata parameter 'copyres' to provide a mechanism to copy resources (images etc) with the entry
Updates copyres so files are gathered upfront and available in templates as "respaths" and "resfilenames"
Also creates change events for hooks.
Change sitemap to exclude resources (can add via config SITEMAP_RESOURCE_EXT, excluding images/video)
updated list
Changed metadata value from copyres: to copy:
Added entry images to sitemap
Added os.path functions to Jinja filter
Added resources list to cache entry so modifications are tracked via entry.modified
Added config CONTENT_WHITELIST to specify content extension(s) an graceful warning for parsing issues
Change CONTENT_WHITELIST to reuse CONTENT_EXTENSION. Updated defaults
Amended commands new and autocompile, removed istext from utils
Updated docs
Merge #159

Conflicts:
	acrylamid/commands.py
	acrylamid/filters/jinja2-templating.py
	acrylamid/readers.py
	acrylamid/utils.py
	acrylamid/views/entry.py