Merge pull request #29 from moroni-pickering/master

xml transform, use Hex Strings instead of BSON object. (mocha tests included)
Added error handling for duplicate IDs and fixed support of custom _id's.
Merge pull request #30 from dvazquez1027/CustomIDs

Added error handling for duplicate IDs and fixed support of custom _id's...
Fixed expect in test for POST of empty XML document.
Merge pull request #31 from dvazquez1027/master

Fixed expect in test for POST of empty XML document.
Fixed documentation and upgraded version
Merge remote-tracking branch 'upstream/master'