GitLab

- ResourceType is now an interface and no an abstract class

    - removed unnecessary lib .jars
    - changed package structure
    - moved enumerations in separate package
    - added MultiType resource to handle content types in a resource
    - moved as much fields as possible to private
    - replaced TimeoutHashMap.java by the new version
    - updated maven build configuration

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Deleted:
 - CoapWellKnownResource - unfinished & unused
 - Resource - merged content into CoapResource.java -> avoids problematic casting in the ResourceServer
 - ResourceHandler - undocumented/unknown purpose & unused
Modified:
 - AbstractCoapMessage -> BUGFIX CoAP Header Option ignored
 - CoapMediaType -> added mime types
 - BasicCoapResource -> added interface description, size estimate & configuration for read and write permissions
 - CoapResource -> changed to more generic datatypes & merged with Resource
 - CoapResourceServer -> changed according to modiied interfaces
 - CoreResource -> now inherits from BasicCoapResource & removed duplicate code & added feature "/.well-known/core filter"
 - Resource Server -> changed according to modified interfaces & enhanced documentation
 - InterfaceTest -> removed encoding error & warning suppress

    - added pom.xml with dependencies
    - removed external jar files
    - moved test classes into separate folder
    - created gradle build for java and OSGI