skip files already minified

If a filename contains 'min.' we assume it is already minified
optimized minification

ScaffoldSourceScript
* remove whitespace around '.'

ScaffoldSourceStyle
* fixed DOCBlock name
+ added rules to remove excessive nested ID selectors
improved XPath expression, clarified inline comments

ScaffoldTemplate
* improved the XPath expression to find nodes which need to be
self-closing
* the output for render is now trimmed
* added individual tiers to the list of valid namespaces
* clarified some inline comments explaining what is done (and why)
documentation and extensibility improvements

ScaffoldTemplateFeatureBlock
* fixed the name in DOCBlock

ScaffoldTemplateFeatureRequire
+ added _getMIMEType method
* changed prepare method to use the _getMIMEType method
Added Content-Security-Policy feature

ScaffoldTemplateFeatureCSP
* introduced new feature-plugin <k:csp /> which allows for sending CSP
v1.0 type headers based on configured attributes and required scripts
and stylesheets (it only uses those as any other means to load
style/script could have been forged)
Merge branch 'master'

scaffold/source/style.class.php