Added KnpPaginatorBundle (dev-master) : composer.json, AppKernel, config.yml & knp_paginator.yml

@see https://github.com/KnpLabs/KnpPaginatorBundle
Added CraueFormFlowBundle (dev-master) : composer.json & AppKernel

@see https://github.com/craue/CraueFormFlowBundle
Added MopaBootstrapBundle (2.2.x@dev) (NO SASS)

@see https://github.com/phiamo/MopaBootstrapBundle
composer.json : Changed symfony/assetic-bundle version from 2.1.* to 2.3.* (solves bug assetic:dump --env=prod)

See http://stackoverflow.com/questions/16655664/symfony-2-assetic-fatal-error-class-assetic-util-pathutils-not-found-on-asset
app/config/config.yml : Added assetic.filters.less (http://lesscss.org/)

For MopaBootstrapBundle, @see https://github.com/phiamo/MopaBootstrapBundle/blob/master/Resources/doc/less-installation.md
Added app/Resources/MopaBootstrapBundle/views/{base,layout}.html.twig : Copy-pasted from MopaBootstrapBundle::base.html.twig
app/config/config.yml : Added c/o assetic.filters.{cssembed,yui_css,yui_js} (from MopaBootstrapBundle documentation)

@see https://github.com/phiamo/MopaBootstrapBundle/blob/master/Resources/doc/assetic-configuration.md
doc/phpuml-ed/.gitkeep & .gitignore
composer.json : Updated rest-bundle version to 0.13.*@dev
composer.json : Changed name of project to fabic/symfony-playground.
composer.json : Altered dep. twitter/bootstrap:dev-master to twbs/bootstrap:2.*