Fixed tables appearance (no borders)
Several improvements:
* changed the slide "Why Bio4j?" to a concise definition of Bio4j;
* moved the slide about the cloud to the introductory justification of the chosen technologies;
* added a slide with the domain-model with highlighted modules;
* added a slide "How others use Bio4j";
* merged the two history slides;
* moved numbers to the domain model slide;
* minor rearrangements and typo fixes;
* added a link to the github repo with the slides sources;