Release of Modularized BioTop Version

[Holger Stenzhorn]

Recently we have undertaken quite some work on modularizing BioTop and
are happy to publish our first release on that on our webpage
http://purl.org/biotop. We invite the community to give comments and
suggestions to out work!

Quick Summary:

In order to move toward modularization, a significant amount of BioTop
classes were moved to a new ontology, named ChemTop. Our
modularization work is bound to the following principles

* The boundary of modules should coincide a given subdomain.
* Modules follow the same principles of upper-level arrangement.
* Modules should be dimensioned in a way that they classify rapidly.
* Modules that cover neighbour subdomains may exhibit a limited
degree of overlap.
* Bridging files link modules between themselves as well as with
upper-level ontologies.

Further, the following alignment efforts have been carried out

* Upper-level ontology BFO
* OBO Relation Ontology RO
* UMLS Semantic Network SN