adds support for PTY mode
adds convenience method mustRun
attempts to fix tests on Travis
adds cache for isPtySupported()
Extract new base test class KernelTestClass

Ideal base class that needs access to a Kernel but not a Client such as
when testing a Command.
[Form] Changed Form::getErrors() to return an iterator and added two optional parameters $deep and $flatten
[Form] Changed the default value of $flatten in Form::getErrors() to true
Added Bulgarian translation for security component
minor #10141 [Security] added Bulgarian translation (RoumenDamianoff)

This PR was submitted for the 2.3-dev branch but it was merged into the 2.3 branch instead (closes #10141).

Discussion
----------

[Security] added Bulgarian translation

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

Commits
-------

8fceeac Added Bulgarian translation for security component
add zh_TW validator translations
minor #10144 [Validator][Translation] add zh_TW validator translations (RickySu)

This PR was merged into the 2.3 branch.

Discussion
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[Validator][Translation] add zh_TW validator translations

add Traditional Chinese validator translations.

Commits
-------

c755e85 add zh_TW validator translations
Added delta for Request comparison

Sometimes, tests are failing because REQUEST_TIME
changes between the creation of the various sub-requests.

By using delta, we allow maximum of second of difference.

Example: https://travis-ci.org/symfony/symfony/jobs/17668158#L511
minor #10143 [Tests] [HttpKernel] Added delta for Request comparison (lavoiesl)

This PR was submitted for the 2.3-dev branch but it was merged into the 2.3 branch instead (closes #10143).

Discussion
----------

[Tests] [HttpKernel] Added delta for Request comparison

| Q             | A
| ------------- | ---
| Bug fix?      | yes (in tests only)
| New feature?  | -
| BC breaks?    | -
| Deprecations? | -
| Tests pass?   | yes
| Fixed tickets | -
| License       | MIT
| Doc PR        | -

Sometimes, tests are failing because REQUEST_TIME changes between the creation of the various sub-requests.

By using delta, we allow a maximum of one second of difference.
Since this is a shady behaviour, I added minimal explanation as comments

Example: https://travis-ci.org/symfony/symfony/jobs/17668158#L511

Commits
-------

3a67309 [Tests] [HttpKernel] Added delta for Request comparison
[HttpFoundation] fixed typo
Revert "bug #10091 [Translation] Update PluralizationRules.php (guilhermeblanco)"

This reverts commit 61625b466d7b569abe3a0ca3c77a76a4f8467240, reversing
changes made to 35585888913a5d0459a1d3213a90ad3c0ec70e22.
[Form] Update DateTime objects only if the actual value has changed
bug #10151 [Form] Update DateTime objects only if the actual value has changed (peterrehm)

This PR was squashed before being merged into the 2.3 branch (closes #10151).

Discussion
----------

[Form] Update DateTime objects only if the actual value has changed

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

Right now the Form component replaces DateTime fields with new Objects, therefore the hash is changing.
This leads to unnecessary database updated when working with doctrine. With this patch the DateTime object
of the actual entity is only replaced if the value has been changed.

Commits
-------

1f22d3a [Form] Update DateTime objects only if the actual value has changed
[Translation] [Loader] Add INI_SCANNER_RAW to parse ini files

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | yes
| Deprecations? | no
| Tests pass?   | no
| Fixed tickets | 
| License       | MIT
| Doc PR        | 

INI_SCANNER_RAW change the default scanner mode of parse_ini_files to parse all values without evaluate. This allow values with single quotes, "no" and "false" and raise an error if you use the deprecated "#" as comment character.
This change is specially good for shared translations, because a translator haven't to know that he can't use a few restricted terms.
And has a residual improvement: it's twice fast that use the default value (INI_SCANNER_NORMAL) in my tests
Use inline images instead of asset() function

For compatibility to other projects using assert() should not be used in webProfiler-templates.
Further compress icon