Update core.js
Update connection.js
Fixed - missing var, poluting global variables
Merge pull request #1173 from dahinir/patch-2

Update connection.js
Merge pull request #1172 from dahinir/patch-1

Update core.js
Merge pull request #1174 from dainis/fix-global-var-leak

Fixed - missing var, poluting global variables
Accept messages up to max bson wire message size, NODE-184