Update rapid_prototyping.rst

Fixed a few grammar mistakes
Update rapid_prototyping.rst
Update installation.rst

Fixed Grammar
Update your_first_block.rst

Grammar fix
Merge pull request #168 from waldermort/patch-3

Update your_first_block.rst
Merge pull request #167 from waldermort/patch-2

Update installation.rst
Merge pull request #166 from waldermort/patch-1

Update rapid_prototyping.rst
update composer.json
fix phpdoc
Add Symfony v2.5 to travis
Merge pull request #170 from interstroom/master

Add Symfony v2.5 to travis
Added php 5.6 to .travis.yml