update gitignore to exclude some v8/node generated files
update gitignore to exclude some v8/node generated files

sethmcl/nodeunit,zuazo-forks/nodeunit,caolan/nodeunit,isaacs/nodeunit,ExtPoint/extnodeunit,hildjj/nodeunit,BuZZ-dEE/nodeunit,BuZZ-dEE/nodeunit,sethmcl/nodeunit,hildjj/nodeunit,caolan/nodeunit,ExtPoint/extnodeunit,robert-berg/rjberg-nodeunit