This commit adds an argument to `SqlString.escape()`, the `collapse` argument.
This is mostly here for some very niche situations where you want to compare something
that isn't space delimited on the DB side with a change you might be making.

For example, perhaps you have an enum (ugh) declared as `colors('red', 'green', 'blue')`.
Maybe you want to change it to `colors('red', 'green', 'blue', 'yellow')`, but first need
to make sure that the DB hasn't been altered. You'll likely get back
`colors('red','green','blue')` or `colors('red','green','blue','yellow')` with an utter
lack of spaces if you call for the table definition.

Hence the safest way to compare is if you can call `escape` on your list of options in
such a way that the options aren't space separated. It's really tricky to remove or add
spaces just for comparison at any other step, especially if you have silly inputs.
Obviously it's a fairly fringe case. There are a few other cases where it might come up.

Pretty much `['dog', 'cat', 'owl']` will escape to `'dog','cat','owl'` instead of `'dog', 'cat', 'owl'` if `collapse` argument is `true`.

There are now examples in appropriate unit tests. They pass.
Merge branch 'patch-1' of https://github.com/dgsan/node-mysql into patch-1

* 'patch-1' of https://github.com/dgsan/node-mysql:
  Update lib/protocol/SqlString.js

Conflicts:
	lib/protocol/SqlString.js