Request to merge Release/v3.3.1b into master

Changes

• KeyError issue fixed, closes #3 (closed)
• KeyError issue with json_send when sending emails with attachments fixed
• Tests added...finally
• Additional print() statements removed
• Gitlab CI configured
• internalMethods.py renamed to utils.py

Deprecations

• get_inbox(), get_draft_messages(), get_deleted_messages, and get_sent_messages() replaced with inbox(), draft_messages(), etc. To be completely removed in pyOutlook 1.0
• add_attachment() deprecated on NewMessage, replaced with attach(). No longer requires file_bytes to be base64 encoded. To be completely removed in pyOutlook 1.0.