Use symfony_env_* variables to tail logs

Right now the log tail is hardcoded to prod.log and dev.log, which is not always the desired behaviour. Using the symfony_env_* variables seems more appropiate
Merge pull request #405 from acasademont/patch-1

Use symfony_env_* variables to tail logs
Prepare 2.3.0 release
Bump version to 2.3.1.dev
set symfony environment prior calling composer install
updated spec file
Merge pull request #412 from abarani/composer-env

set symfony environment prior calling composer install
Add web_path variable
Merge pull request #415 from robertobermejo/issue_414

Add web_path variable