document both cache class loader the ApcClassLoader and the XcacheClassLoader
documentation for the DebugClassLoader
documentation for the MapClassLoader class
add an introduction and documentation for the ClassLoader class
add versionadded directives for new classes
fixes thanks to @WouterJ
fix markup of links
fix link to Class Loader docs
Fixing wrong parameter name in redirecting in config
add note for the HTML5 date format
[forms] Remove tip for skipping validation group section
[cookbook/form/dynamic_form_modification] Fix sample code for dynamic generation of submitted forms (3rd section)
Update installation.rst

typo in cookbook/bundle/installation
[Components][Config][Definition] Fix code sample
[#3003] Adding details about validation for 4096 password length and protecting against attacks with custom password encoders
Merge pull request #3009 from symfony/issue-3003-password-length

[#3003] 4096 Password length details
Merge pull request #2913 from xabbuh/issue-2834

documentation for the Class Loader component
[#2913] Minor tweaks to the built-out class loader component docs by @xabbuh
Added hint about modifying an unmapped form field
Fixed typos