Document and refactor 'parsePackageDescription'.
Document and refactor 'parsePackageDescription'.

Hopefully this makes this function more understandable and easier to
modify.

edsko/cabal,gridaphobe/cabal,bennofs/cabal,bennofs/cabal,triplepointfive/cabal,randen/cabal,seereason/cabal,edsko/cabal,mydaum/cabal,martinvlk/cabal,themoritz/cabal,alphaHeavy/cabal,Peaker/cabal,valderman/cabal,gbaz/cabal,x-y-z/cabal,kolmodin/cabal,plow-technologies/cabal,beni55/cabal,thomie/cabal,mmakowski/cabal,fugyk/cabal,martinvlk/cabal,plow-technologies/cabal,ian-ross/cabal,Helkafen/cabal,trskop/cabal,anton-dessiatov/cabal,fugyk/cabal,headprogrammingczar/cabal,seereason/cabal,gbaz/cabal,sopvop/cabal,rimmington/cabal,fpco/cabal,sopvop/cabal,plumlife/cabal,lukexi/cabal,anton-dessiatov/cabal,lukexi/cabal,eric-stanley/cabal,Heather/cabal,ghc-android/cabal,alphaHeavy/cabal,eric-stanley/cabal,beni55/cabal,triplepointfive/cabal,sopvop/cabal,rimmington/cabal,typelead/epm,mydaum/cabal,garetxe/cabal,corngood/cabal,trskop/cabal,x-y-z/cabal,plumlife/cabal,themoritz/cabal,headprogrammingczar/cabal,typelead/epm,garetxe/cabal,ian-ross/cabal,randen/cabal,Heather/cabal,mightybyte/cabal,thoughtpolice/cabal,mightybyte/cabal,themoritz/cabal,thomie/cabal,ghc-android/cabal,corngood/cabal,kosmikus/cabal,kolmodin/cabal,enolan/cabal,fpco/cabal,Peaker/cabal,christiaanb/cabal,Helkafen/cabal,thoughtpolice/cabal,mmakowski/cabal,christiaanb/cabal,gridaphobe/cabal,enolan/cabal,valderman/cabal,kosmikus/cabal