Extend DEVELOP and THANKS file

I added the informations for vagrant into the DEVELOP file.
Also I noted that the line wrapping was not realy consistent so I made sure that everyline will not scratch the textwidth=80 with vim.
Please take a look on it before merging. It may be that I changed a line which was fine. I took care of it but it might be that I overlooked something.

Last but not least I added myself into THANKS.
s/Therefore/There/