ISSUE #11300: Improve Routing Syntax Import Error

modified FileLoaderLoadException message to present the previous (Parse)Exception first
Add test and small code fix
Addition of the symfony license text
- Removed spaces around the concation dots to be more consitent
- adjusted some formatting
Merge remote-tracking branch 'upstream/master'
removed some more spaces
return empty metadata collection if none do exist

The PropertyMetadataContainerInterface defines that the method
getPropertyMetadata() has to return an empty collection if no
metadata have been configured for the given property. Though, its
implementation in the ClassMetadata class didn't check for
existence of such metadata. This behavior led to unexpected PHP
notices when validating a property or a property value of a property
without any configured constraints (only affects the new 2.5 API).
Additionally, the getMemberMetadatas() didn't check for existing
array keys as well which has also been fixed.
[DomCrawler] fix the axes handling in a bc way

The previous fix in #11548 for handling XPath axes was not backward
compatible. In previous Symfony versions the Crawler handled nodes
by holding a "fake root node". This must be taken into account when
evaluating (relativizing) XPath expressions.
[Console][ProgressBar] Developer experience
 - Create getProgress/setProgress methods to replace getStep/setCurrent
 - ProgressBar::setCurrent should auto-start the ProgressBar.
 - You should be able to pass max to start
 - getStepWidth is internal information that should not be public
 - when verbosity set to quiet, the progress bar does not even need to
   execute all the logic to generate output that is then thrown away
[Console][ProgressBar] Allow to advance past max.
[Console][ProgressBar] Developer experience:
 - Removed barCharOriginal
 - getProgressPercent should return float instead of int.
 - Minor refactoring
[FrameworkBundle] Fixed validator factory definition when the Validator API is "auto" for PHP < 5.3.9
fix handling of nullable XML attributes

As @Tobion pointed out in #11394, true and 1 are valid values in
boolean XML attributes. The XmlFileLoader didn't handle 1 values
properly.
[Validator] Fixed Constraint class to not destroy custom groups upon serialization
bug #11584 [FrameworkBundle] Fixed validator factory definition when the Validator API is "auto" for PHP < 5.3.9 (webmozart)

This PR was merged into the 2.5 branch.

Discussion
----------

[FrameworkBundle] Fixed validator factory definition when the Validator API is "auto" for PHP < 5.3.9

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #11580
| License       | MIT
| Doc PR        | -

Commits
-------

a74b758 [FrameworkBundle] Fixed validator factory definition when the Validator API is "auto" for PHP < 5.3.9
[Translation] added method to expose collected messages
check for the correct field type

HTML allow to define different form fields with the same name.
Imagine the following form:

    <html>
        <body>
            <form action="/">
                <input type="hidden" name="option" value="default">
                <input type="radio" name="option" value="A">
                <input type="radio" name="option" value="B">
                <input type="hidden" name="settings[1]" value="0">
                <input type="checkbox" name="settings[1]" value="1" id="setting-1">
                <button>klickme</button>
            </form>
        </body>
    </html>

Since the `FormFieldRegistry` can only handle one field per name, the
hidden field option is registered first before the radio field with
the same name is evaluated. Thus, the `FormFieldRegistry` returns an
`InputFormField` instance on which the `addChoices()` method can not
be called.
bug #11691 [Validator] Fixed Constraint class to not destroy custom groups upon serialization (webmozart)

This PR was merged into the 2.6-dev branch.

Discussion
----------

[Validator] Fixed Constraint class to not destroy custom groups upon serialization

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #11638
| License       | MIT
| Doc PR        | -

Commits
-------

d405f43 [Validator] Fixed Constraint class to not destroy custom groups upon serialization
minor #11615 [Validator] return empty metadata collection if none do exist (xabbuh)

This PR was merged into the 2.3 branch.

Discussion
----------

[Validator] return empty metadata collection if none do exist

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets |
| License       | MIT
| Doc PR        | [The reference to the documentation PR if any]

Backport of #11614 for Symfony 2.3 and 2.4.

Commits
-------

f5bc18d return empty metadata collection if none do exist
[Validators] Fixed failing tests requiring ICU 52.1 which are skipped otherwise