Add quatation to file path

Temporary fix for compilation error on 2019.3

- This is only a workaround for the compilation error but doesn't solve the
  actual problem. It's to be fixed in a future version.

Make FFmpegPipe public

Update README

Bug fix on render texture allocation

- Fixed: Temporary render texture doesn't have proper depth.
- Improved: Supports MSAA options.

Merge pull request #30 from keijiro/dev-0.2.0

Dev 0.2.0

bugfix: depth test problem

Fixed WebM options

bugfix: depth test problem

Updated README