bug fixing (+Comments by Carina)

1. Introduction
"The most important message is to use RDF not find the best
representation for your data, but to be explicit in how you represent
your data."
-> Grammar error? I am not getting the point of this sentence.

2. General Principles
"Why sometimes relationship labels may be omitted"
-> Why is this section here? Seems not to belong here. Should be moved
into Section 6.

4. Step 1 - First paragraph
Still talking about pets, instead of the concepts used in the example.

5. Step 2 - First paragraph
Some questions separated by comma. Should have question marks instead.

10. Step 7 - Tools available for validation
c&p error - "Below is a brief overview of tools that may assist the
triple generation."

added namespaces for genomic data