Create package.json

There may be some benefits to having a package.json, but the primary reason i'm interested in submitting this is for the jspm override entry, with it we can include select2 as simply as:

http://jsbin.com/upOtaXIR/2/edit

Any questions please shout!
Correcting git repository url
Merge pull request #1943 from Jarreddebeer/patch-1

Create package.json