feature#1189 added a way to add custom escaping strategies (fabpot)

This PR was merged into the master branch.

Discussion
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added a way to add custom escaping strategies

This adds the possibility to define custom escapers that can be used with the `escape` filter.

That would close #1178 and #1177, but I'm not sure that this is a good idea.

What do you think?

Commits
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55f8b27 added a way to add custom escaping strategies

diff --cc lib/Twig/Extension/Core.php
Simple merge