[WebBundle] Fix invalid html markup for payments forms

Added easier way to change states & hide editing for non super admins
[AttributeBundle] Write specs for the LoadMetadataSubscriber
[VariationBundle] Write specs for the LoadMetadataSubscriber
Removed duplicate stripe.secret_key parameter
[AttributeBundle] Write specs for the container extension
[VariationBundle] Write common spec example for the container extension
Merge pull request #2229 from rvanlaarhoven/patch-1

Removed duplicate stripe.secret_key parameter
Fix legacy payum getNotification
Fix exit code for travis scripts
Tweak the pdf generation
Fix language switching
Fix free product promotion scenario
Fix the formatting discount bug on travis
Merge pull request #2231 from winzou/fix/payum

Fix legacy payum getNotification
Merge pull request #2096 from stloyd/bugfix/payments_forms

[WebBundle] Fix invalid html markup for payments forms
Merge pull request #2226 from adamelso/spec-coverage-on-metadata-manipulation

[AttributeBundle][VariationBundle] Spec coverage on Doctrine metadata subscribers and container extensions
[SequenceSpec] Missing spec
[Taxonomy] Fixed #1543 creating taxons with the same name
Properly close javascripts block and remove superfluous endblock
Merge pull request #2238 from rskuipers/patch-1

[WebBundle] Properly close javascripts block and remove superfluous endblock