symfony 4.0 support

Good news everyone! New release includes #12 symfony 4.0 support, thanks @duxet

bugfix release - when no geo information found about ip

Includes:

• #10 - Check indexes when no geo information is available. Thanks @SG5
• #11 - Drop hhvm support (at least in tests), because phpunit does not support it anymore. Thanks @SG5

fix backwards compatibility broken in 0.2.1

#7 fixes breaking changes introduced in 0.2.1

option which file to download during composer install

• #6 added the possibility to specify which mmdb to download during composer install (thanks @jaumebosch )

v0.2.0

• added php7.0 tests
• fixed symfony yml deprecations (#2 )
• added support of maxmind-reader v1.0
• removed deprecated composer CommandEvent usage