CS and documentation fixes

Updated docs to support IDE autocompletion and hinting. Re-ordered "use" statements, and removed unnecessary ones. Fixed some class references (e.g. "InvalidArgumentException" becomes "\InvalidArgumentException").

Additional revisions from @jmikola. Closes #549
Remove unused args/code in UnitOfWork::doMerge()
Refactor if/else in DocumentRepository::find()
Throw exception if removed document encountered during flush

Fixes c8fafa99c7fb6733d604ee2378de477833e53e9a
Merge pull request #582 from doctrine/gh549-cs-doc-updates

CS/doc fixes and code cleanup
missing loggable cursor

throwing an error
Merge pull request #583 from tpae/master

Added use Doctrine\ODM\MongoDB\LoggableCursor; in DocumentPersister
Strip leading backslash for doc classes in DocumentManager

Related to: doctrine/doctrine2@0424d870999c9fb0a044a8b5773f250376d2368f

See: #585 and #586
Fix several instances of doubled words
Merge pull request #590 from jbafford/doubled-words-fix

Fix several instances of doubled words in the documentation
Prepare projections in Query\Builder
Fix sort/limit/skip preparation in DocumentPersister load methods

Previously, load() and loadAll() did not prepare sort criteria before applying it to a base Cursor. The loadAll() method also only applied sort/limit/skip options to the base Cursor, which made them unavailable after wrapping. Also updated related doc blocks and renamed some arguments for consistency.

Fixes doctrine/DoctrineMongoODMModule#70
Regression test DocumentPersister::loadAll() and cursor recreation

See: doctrine/DoctrineMongoODMModule#70
Merge pull request #592 from doctrine/document-persister-prep

Fix preperation of Cursor options in DocumentPersister load methods
Move Type classes from Mapping to Types namespace

This is consistent with Doctrine ORM and other ODM projects.
Use Type::getType() instead of calling private Type constructor
Merge pull request #546 from doctrine/refactor-types

Refactor types to be consistent with other Doctrine adapters
Throw exception in DateType when conversion to MongoDate fails

This reverts a change introduced in b702787869dcccfc1ab203a1616527662c3d661d, which would store an ISO8601 date string on error.
Add unit tests for DateType
Merge pull request #540 from doctrine/datetype-tests

Throw exception for DateType conversion error and add tests