core: text message problem with unicode (UTF8) letters.

Required Information

• Operating system: CentOS 6.x
• PHP version: 5.6
• PHP Telegram Bot version: 0.44.1
• Using MySQL database: no
• MySQL version:
• Update Method: Webhook
• Self-signed certificate: no
• RAW update (if available):

Expected behaviour

sendMessage must send unicode text to telegram.

Actual behaviour

sendMessage does not send anything to telegram unless I change text message to non-unicode (English for example).

Steps to reproduce

Extra details

Example code: $data['text'] = "ارسال پاسخ ...";