fix providers
fix provider tests
fix phpdoc
update test methods names
Merge pull request #365 from pyrech/fix-failing-tests

[WIP] Fix failing tests
Fix string formatting
Fix #367
Introduce AbstractHttpProvider

Fix #359
Various fixes thanks to Scrutinizer
More tweaks
Install geoip ext on travis-ci
Call parent constructor in Geoip provider
simplify travis-ci config
fix geoip tests
more fixes on Geoip tests
fix HHVM builds on Travis

The `pecl` command is not available for HHVM environments. So, we
should skip installing packages required for the GeoIP feature. This
resolves #373.
Merge pull request #374 from xabbuh/travis-hhvm

fix HHVM builds on Travis
fix Yandex provider exception messages
rewrite readme
minor fixes on the doc