[SecurityBundle] avoid unneeded work
[CssSelector] added the license of the Python library we ported to PHP
[HttpFoundation] removed wrong HTTP header
minor #13103 [SecurityBundle] avoid unneeded work (fabpot)

This PR was merged into the 2.3 branch.

Discussion
----------

[SecurityBundle] avoid unneeded work

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #13018
| License       | MIT
| Doc PR        | n/a

Commits
-------

8135727 [SecurityBundle] avoid unneeded work
minor #13104 [CssSelector] added the license of the Python library we ported to PHP (fabpot)

This PR was merged into the 2.3 branch.

Discussion
----------

[CssSelector] added the license of the Python library we ported to PHP

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #11894
| License       | MIT
| Doc PR        | n/a

Commits
-------

fa36b98 [CssSelector] added the license of the Python library we ported to PHP
[TwigBridge] fix form requirement
minor #13118 [TwigBridge] fix form requirement (nicolas-grekas)

This PR was merged into the 2.3 branch.

Discussion
----------

[TwigBridge] fix form requirement

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | -
| License       | MIT
| Doc PR        | -

Commits
-------

d9053d9 [TwigBridge] fix form requirement
minor #13115 [HttpFoundation] removed wrong HTTP header (fabpot)

This PR was merged into the 2.3 branch.

Discussion
----------

[HttpFoundation] removed wrong HTTP header

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #12194
| License       | MIT
| Doc PR        | n/a

Commits
-------

73dddac [HttpFoundation] removed wrong HTTP header
[travis] reorder matrix + prevent "Killed" jobs
minor #13123 [travis] reorder matrix + prevent "Killed" jobs (nicolas-grekas)

This PR was merged into the 2.3 branch.

Discussion
----------

[travis] reorder matrix + prevent "Killed" jobs

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | -
| License       | MIT
| Doc PR        | -

The new --prefer-lowest matrix line fails randomly with ["Killed" message](http://docs.travis-ci.com/user/common-build-problems/#My-build-script-is-killed-without-any-error).
Lets try reducing concurrency on this one.
The matrix is also reordered so that the slowest lines are started first.

Commits
-------

b1d47e9 [travis] reorder matrix + prevent "Killed" jobs
Use the correct cssselect library name in docblocks.

The original python library is called cssselect, not cssselector.
Update the note about origins of the CssSelector component.

The last rewrite is based on the cssselect which is no longer part of lxml, but was extracted as an independent library.
minor #13132 [CssSelector] Use the correct cssselect library name in docblocks. (jakzal)

This PR was merged into the 2.3 branch.

Discussion
----------

[CssSelector] Use the correct cssselect library name in docblocks.

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | no
| Fixed tickets | #11894
| License       | MIT
| Doc PR        | -

As suggested in #11894, the original python library is called [cssselect](https://github.com/SimonSapin/cssselect), not cssselector.

I also updated the README, as the cssselect was extracted as an independent library and it's no longer part of lxml.

Commits
-------

55f0d9e Update the note about origins of the CssSelector component.
1997b12 Use the correct cssselect library name in docblocks.
[FrameworkBundle] added a test router for the buil-in web server