• Place all commands into an anonymous namespace. Prevents needless symbol pollution across the SwiftShader library.
• Don't use a mix of class and struct for commands - stick to using class.
• Prefix commands with 'Cmd' to avoid a symbol collision with Win32 ResetEvent.
• Remove pointless 'protected' modifiers.

Bug: b/116336664
Change-Id: I05a7d5a196f1b49144be7a685a0923dee1c55fbc
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/38909Tested-by: Ben Clayton <bclayton@google.com>
Reviewed-by: Chris Forbes <chrisforbes@google.com>
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>