Update README.md
Update README.md
register test fixtures command by tag
Moved project validators to core bundle
Changed CatrowebBundle to WebBundle
Merge branch 'master' of https://github.com/Catrobat/Catroweb-Symfony into chartinger
added project import command
Merge branch 'Tutorial-FristSteps' of https://github.com/Catrobat/Catroweb-Symfony into Tutorial-FristSteps