Debug and Error handling related issues

[dmnsgn]

Debug:

• Replace ctx.debug with ctx.set({ debug: }) Replace ctx.debug with ctx.set({ debug: }) #44 (PR)
• Use webgl-debug in debug mode Use webgl-debug in debug mode #40
• debugCommands list is not cleared debugCommands list is not cleared #39 (PR)
• Get rid of GraphViz dot code generation Get rid of GraphViz dot code generation #28 (PR)

Error:

• Runtime error handling Runtime error handling #54
• Verify pipeline parameters Verify pipeline parameters #20