accord avec "la plupart"

cf http://fr.wiktionary.org/wiki/plupart#Note sauf archaïsme, le verbe est au pluriel
Merge pull request #676 from JLuc/master

accord avec "la plupart"
[nl] Chapter 02. Review, include new command output and add header.

   Reviewed translations and made them more consistent and in line with
   the recommendations of the Dutch language institute.
   Added a header to that effect to the file.
   Included the new modified command output.
[nl] Chapter 02. More commands straightened

     On second viewing there were more commands to be corrected.
Merge branch 'chapter02' of github.com:Cpt-xx/progit into chapter02

Conflicts:
	nl/02-git-basics/01-chapter2.markdown