extracts some code to dedicated library
adjusts visibility
made lazy-loading more generic
fixes null-handling behavior when serializing null object (closes #233)
fixes tab
Add InitializedObjectConstructor as a test double for DoctrineObjectConstructor.

Add tests to BaseSerializationTest:
* testNull when expecting types
* testNumerics when expecting numeric types
* testDateTime
* testDeserializingNull when using InitializedObjectConstructor

Add content for blog_post_unauthored and date_time:
* JsonSerializationTest
* xml/blog_post_unauthored.xml
* xml/date_time.xml
* yml/blog_post_unauthored.yml
* yml/date_time.yml

So, from the phpunit test results, we see:
* fails when serializing a simple DateTime
* error when deserialing a null when expecting a DateTime
* error: no support for the "float" alias for "double"
* error when deserializing: a null value will not overwrite a non-null property in the initialized object

Conflicts:

	Tests/Serializer/JsonSerializationTest.php
GraphNavigator support for "float" alias.
fixes Date deserialization
fixes overwriting default values when explicit null is passed (closes #222)
extracts standalone library to dedicated repository
fixes formatting
relaxes symfony constraint
exclude 3.*
Update composer.json
add the fact that there is a 0.10 release
refactored docs
makes visitors public
Merge pull request #245 from lsmith77/fix_upgrading

add the fact that there is a 0.10 release
updates docs to use jms_serializer as id for serializer
fixes service id (closes #246)