Fix explicit .self errors in Xcode 11

[jojost1]

Description

Adds some explicit self.

Motivation and Context

Fixes issue #157

How Has This Been Tested?

No functional changes, only extra references to self. Builds fine.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Non-functional change (Updating Documentation, CI automation, etc..)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.

[jojost1]

@AppPear any chance you could merge this one?