Added missing command "odm:schema:update"

[Doctrine/ODM/MongoDB/Tools/Console/Command/Schema/UpdateCommand.php](
../blob/master/lib/Doctrine/ODM/MongoDB/Tools/Console/Command/Schema/UpdateCommand.php)
Serialize ClassMetadata::$associationMappings correctly

Prior to this commit, APC cached ClassMetadata was completely broken. ClassMetadata::__sleep()
does not return associationMappings, which menas that when it is written to cache, that field
is not added.

When it is read from the cache it is simply an empty array. In certain cases this can cause
problems (data loss).
Merge pull request #806 from researchgate/serialize-classmetadata

Serialize ClassMetadata::$associationMappings correctly
Application::setHelperSet() must be called before addCommands()

Application::add() calls Command::setApplication(), which in turn assigns the Application's current HelperSet to the Command. Therefore, we need to set the HelperSet before registering any Commands.

This fixes a bug that was introduced in a49d20d1906523bc4845c89666bef9f41794f1b1.
Construct query builder in QueryCommand (fixes #801)

Since #752, the repository find methods return arrays instead of cursors in order to be consistent with the common repository interface. With this change, a query builder is used, and the skip/limit/hydrate options can be applied to the builder directly.
Dump QueryCommand result documents individually, using correct depth

Previously, the array of results was dumped, so the effective depth was reduced by one. Dumping the result documents themselves with the specified depth seems more intuitive.
Merge pull request #808 from doctrine/fix-queryCommand

Fix CLI sandbox command DM helper and QueryCommand
Merge pull request #797 from stephandesouza/patch-1

Add missing UpdateCommand in console documentation
Merge branch 'master' of github.com:doctrine/mongodb-odm into history-types