Moved index entries within text bodies. Added description of text labels.
Finished first draft of references chapter.
Added further keyword explanations.
Added keyword index entries. Began the new chapter "PP3 and LaTeX".
Added keyword lists as an overview for me.
Spell checking and some restructuring.
Added table with vector downloads. Minor improvements.
Französisches Wikipedia erwähnt.
Added explanation of Flamsteed and HD numbers.
Added things about astronomical terms.