turtle fixes post-merge with editCode

* move lineStylePatternOptions so they are available even when Blockly is not available
* add a BlocklyApps.usingBlockly check before overriding a Blockly random generator function
* add a comment about why we're sharing from a different context for the new skins
* in the interpreter loop, continue to call executeTuple() until it returns false after we've completed our last step() - this ensures that the last command draws to completion.
* add back a check for Turtle.response before dereferencing it