Fix various typos in chapters 1-3
The G in {A,L}GPL does not stand for GNU

but for general...
Cannot should be can not in certain phrases

See http://oxforddictionaries.com/definition/english/cannot?q=cannot
On the one hand..., on the other hand...
Merge pull request #6 from schierlm/typosquatting

michael schierl: Fixing typos in chapters 1-3