Switch to using setOnInsert

[Glavin001]

See http://docs.mongodb.org/manual/reference/operator/update/setOnInsert/#up._S_setOnInsert

Instead of trying to update and then inserting on update failure and trying to update after insert; simply use setOnInsert in the initial update! See https://github.com/Glavin001/Cobra/blob/master/server/index.js#L237-L262

[Glavin001]

Performance is actually not as good:

• every request is now larger and takes longer to process
• versus having 1 failed update an hour and 1 required insert, and then 1 final update: 2 extra (3 total) requests per hour

[Glavin001]

• The top results are using setOnInsert and averaging around 20 or less.
  • Also notice the increase netIn and locked db! Wow!
• The lower (more recent) results are using the original method with a failing update and an insert then retry update request. It successfully reaches 100 updates per second, easy.

[Glavin001]

Implemented on branch https://github.com/Glavin001/Cobra/tree/setOnInsert