package.json - Update with latest version of couchapp - to solve cross-platform issues in older couchapp versions

Latest version of couchapp has done a great deal on cross-platform independence.

When trying to create a local NPM registry from a WindowsXP machine, I found difficutlies origined with cross-platformed, which were solved after `npm install couchapp@0.9.1`.
I knew it only because I was involved in their progress... I hope when others encountered this problem they did not give up...

 - tested on my windowsXP3 :)