v1.7.1

Version 1.7.1

• Added the import block to the json_ld top level block, to allow adding a @import statement with one or more URI-s at the top of the generated context file.
• When generating a context file with an aliased term (see the known_as property) an extra information is added to the generated HTML file.
• Added the capability to handle HTML templates containing HTML fragments only. The result can be imported into a specification instead of keeping it as a separate file.
• Introduced the upper_union and range_union boolean flags for classes and, respectively, properties. If set to true, the superclass, respectively range settings with several class references mean the disjunction of the classes, as opposed to the (default) conjunction. This formally affects the turtle and json-ld versions of the vocabulary (which use the owl:unionOf construct); the HTML description uses now the ⊓ and ⊔ characters to denote these. This allows to say: "instances of this class are of type either this, this, or this".
• Introduced the one_of keys for classes, datatypes, and property ranges. The values list the possible individuals for a class (including a range), and the possible string values for a datatype derived from xsd:string. Furthermore, the pattern key for a datatype can hold a regular expression restricting the acceptable string value.
• Some minor optimization (e.g., removal of unnecessary prefix definition from the generated html/turtle/jsonld).
• Re-edited the README.md file to make it somewhat more readable.