Allow bundle to be used without clients or indexes defined.
Move type configuration into independent method
Refactor documentation
fix some block comment
Make fetchSlice compatible with custom repo method

If a user configures query_builder_method for the doctrine provider, and
does not alias the root entity to equal Provider::ENTITY_ALIAS then a
DQL error will occur during index population.

> [Semantical Error] [...] near 'a.id ASC': Error: 'a' is not defined.

Provider::countObjects already handles this by dynamically fetching the
alias with QueryBuilder::getRootAliases, and Provider::fetchSlice should
be doing the same.

nb. "Provider" refers to FOS\ElasticaBundle\Doctrine\ORM\Provider
Unset fields if no nested fields are defined
Clone entities on delete to preserve ids
Prevent division by zero error
Merge pull request #514 from jvandesande/MultiField

Unset fields if no nested fields are defined
Merge pull request #505 from piotrantosik/fix_docblocks

Fix some block comment
Merge branch 'master' into documentation

Conflicts:
	DependencyInjection/Configuration.php
	README.md
Merge pull request #510 from peterjmit/master

Make fetchSlice compatible with custom repo method
Documentation updates
Merge pull request #435 from merk/documentation

Refactored documentation
Logger enabled with debugging
Update changelog
Update logger documentation based on configuration change
Merge pull request #519 from merk/logger-debug

Change logging to only be enabled in debug mode
Corrected bundle class name in install instructions
Merge pull request #521 from morticue/master

Corrected bundle class name in install instructions