Conflicts:
	src/jio.storage/replicatestorage.js
	test/jio.storage/replicatestorage.tests.js

Attachments are synchronized only of explicitely activated from the jIO configuration.
Replication deletes a document only if it doesn't contain any attachment.

Thanks to Cedric Leninivin for his work on this topic.

/reviewed-on nexedi/jio!42

It allow to check recursively if a storage support bulk.

`jIO.util.stringify` was raising if the value of an object was undefined, this changes fix it and provides the same behaviour as the standard `JSON.stringify`

/reviewed-on nexedi/jio!41

@seb, please review

/reviewed-on !37

/reviewed-on nexedi/jio!35

This helps understanding why browser refuses to open the DB.

Example: Firefox prevent using IndexedDB if browser history is disabled.

/reviewed-on nexedi/jio!33

Fix ReplicateStorage to reduce conflicts during synchronisation.

Creation and modification process now use the same code

/reviewed-on nexedi/jio!29

/reviewed-on nexedi/jio!28

Do not display error in browser not implementing WebSQL.
WebSQLStorage will raise an error is used in such browsers.

JSON.stringify is not stable by design and can not be used to generate the hash.
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify

This commit adds a stable version of JSON.stringify, available at jIO.util.stringify.
Relying on the nearly same string representation will simplify compatibility.