add 180 projection

[luiscerqueira]

Description

Reference to #36

Added support for 180Vr video as an enhancement.

Specific Changes proposed

• Updated the plugin.js by adding a condition if the projection equals 180 and added the logic to map the texture of the video to it.
• Added condition for orbit-orientation-controls.js to limit minimum and maximum rotation if the projection is half of the view
• Added 180 to the validProjections array in the utils.js file
• Added example page 180.html
• Index.html updated with a link to 180 example page
• Added a 180 Vr sample video in the samples folder

Requirements Checklist

• Feature implemented / Bug fixed
• If necessary, more likely in a feature request than a bug fix
  • Unit Tests updated or fixed
  • Docs/guides updated
• Reviewed by Two Core Contributors

[blurymind]

very cool! Hope this gets merged :) 👍

[axten]

cool feature! are there any plans to file a release?