Fixed some typo + Added some awesomeness

[lyrixx]

Note, this will require twig >=1.12

[lyrixx]

What I did:

• I fixed typo with twig engine (the old code did not use Twig Timed engine)

• The configuration is now more flexible:

  web_profiler_extra:
    assetic: false
    assetic:
        enabled : false
  
    # nothing
    assetic: ~
    assetic : true
    assetic :
        enabled: true

• Fixed the template name in the twig panel I the twig panel, the template name are now clickable (works if xdebug or symfony is well configured)

• Shortcut in WDT are now configurable:

  web_profiler_extra:
    assetic :
        display_in_wdt: true

• Removed dead code
• Fixed README

[lyrixx]

WARNING: Do not merge this PR. It's not yet ready:

It broke functional test since the application is booted without debug, so TimedTwigEngine can not be booted because stop_watch is not available.

I need to find a way to extends the current default TwigEngine. I think decoration could be a good solution, but it's not easy with the DIC.

[lyrixx]

Every thing should be good ;)

[lyrixx]

Ok, I think everything is ok

[tristanbes]

Tu peux rebase stp ? j'ai push du code entre temps :-)

[lyrixx]

Voila ;)

[tristanbes]

Thanks for your contrib :-)