adding diagram in the readme

OnToology update

test read in a inner folder

added diagram and owl code for s4agri first working draft

added saref:hasDescription only rdfs:Literal as local restriction

update HTML for revision version and overall diagram

OnToology update

Removed s4city:Measurement.
Removed skos:Concept generalising the solution to broader options.

Updated diagram according to @rgcmme updates

Replaced KeyPerformanceIndicatorValue y KeyPerformanceIndicatorAssessment, since "Value" is misleading.

added diagram for examples and SAREF4CITY validation workshop slides

* Multi-line labels
* URL definitions in isDefinedBy
* The definition of geo:location

OnToology update

Added axiom for local restrictions for the S4CITY ontology

OnToology update

reuse of geosp classes and properties
updated diagram

Modifications about KPI properties and reuse of geoSPARQL at
conceptualisation level

Draft of the HTML description.