Fix React warnings in Bee Grid Editor
Fix React warnings in Bee Grid Editor

selectedX and selectedY are no longer required props on the Grid component (they are not provided in the initial state, so it doesn't make sense for them to be required).

Provide unique key prop to components returned by map functions (which helps React with tracking, internally).

FYI @Hamms

rvarshney/code-dot-org,rvarshney/code-dot-org,rvarshney/code-dot-org,rvarshney/code-dot-org,pickettd/code-dot-org,pickettd/code-dot-org,dillia23/code-dot-org,rvarshney/code-dot-org,rvarshney/code-dot-org,dillia23/code-dot-org,dillia23/code-dot-org,rvarshney/code-dot-org,pickettd/code-dot-org,rvarshney/code-dot-org,pickettd/code-dot-org,pickettd/code-dot-org,dillia23/code-dot-org,dillia23/code-dot-org,dillia23/code-dot-org,dillia23/code-dot-org,pickettd/code-dot-org,pickettd/code-dot-org,dillia23/code-dot-org,pickettd/code-dot-org