Add OLX Exceptions

- add Validation exception

- change exception messages

v2.4.0: - add districts supprort

• add districts support
• add languages support
• add get city by id
• add get region by id

v2.3.1

add users

v2.3.0

Upgrade guzzle 6 & 7

v2.0.0

Support many countries

1.2.0: Merge pull request #4 from abushyk/master

functionality extending (Threads, Users, Messages)

v1.1.1

deactivate advert before delete