Fix language.
Add versionadded
Correct folder name
Added a sidebar about potential deployment problems with ICU
Document ignoreUnreadableDirs

| Q             | A
| ------------- | ---
| Doc fix?      | no
| New docs?     | yes
| Applies to    | 2.3
| Fixed tickets | 2574
Merge branch 'intl' of github.com:bschussek/symfony-docs into bschussek-intl

Conflicts:
	components/index.rst
Merge pull request #2519 from CharlyP/dynamic-form-modification-fix

Remove unused code in the last code sample
Merge pull request #2530 from hhamon/validator_reference_typo

[reference] [validator] fixed wrong option name in the All constraint re...
[#2312] Minor tweaks for new intl component documentation
fixed grammar in example message for CardScheme constraint
[cookbook][doctrine/reverse_engineering] fixed extension prefix for mapping file generated by doctrine:mapping:convert
[cookbook][doctrine/reverse_engineering] fixed output path specification for yml or xml mapping file
[cookbook][doctrine/reverse_engineering] add description to insert namespace
[cookbook][doctrine/reverse_engineering]changed the second command to execute from doctrine:mapping:import to doctrine:mapping:convert
Revert "[#2475] Tweaks to new session on-demand docs"

This reverts commit 7f288dcc476b640cd0c0a81c37a9b0721353be2d.

Reverted because the code change was reverted.
Revert "Merge pull request #2475 from drak/session_demand"

This reverts commit bd3e58e342632671e7fd31369c75ed49bb7ce053, reversing
changes made to 73e5095f59fb6c1b246b4a9688159ade18b74a86.

Reverted because the code change was reverted
Merge branch 'bschussek-intl'
Merge pull request #2499 from WouterJ/commit_comments_20

Fixed Commit comments
Merge pull request #2529 from fabpot/apache-authorization

added a note about php-cgi and Apache
[#2529] Minor tweak thanks to @WouterJ