Queries default value

Added

• Add "queriesDefaultValue" option. If defined, queried instances will have default value corresponding to the value of query "key" in the default value object. If not, the behavior of "default value" will be the same than in previous versions, and will return the full object even for queried instances)
• Add "tags" option.

Changed

• Emit "clean" event over root instance when an "update" is executed on any queried instance. (Full object is modified too).
• Upgrade mercury version and define it as peer dependency.
• Upgrade devDependencies.
• Fix readme examples