fix typo - missing word
typo - change  to
change headers example to use a request header (not a response header)
decorate php function with link to manual
add more descriptive text for book link
Shorten line under 80 chars
lower case request since it's not talking about the class
change to URI to be more consistent. fix typo. lower case Session
change query to request to be more accurate
lower case request
change final bullet to end with period
backtick Request. link to Request API
Refactored OptionsResolver docs to have a better example
Documented ProgressHelper's clear() method.
Added cookbook page about sessions directory.
Add some clarification to Quick Tour Working with Environments

Also, for the session token: identify what the "weird" hex number is, and and replace "weird" with "long" (a more apt description).
The instructions are incomplete.

Added routes and doctrine commands
removed duplicate timestamp limitation notice
XML validation code needs constraint-mapping element

Missing XML information causes errors, has been been problematic for a while. See link for example: http://vvv.tobiassjosten.net/symfony/symfony2-validation-in-xml/
added timestamp limitation notice for datetime