Support jshint-style inline obfuscation options

[joevennix]

It would be nice to declare in the code itself different options for obfuscation. For example:

/* jsobfu memory_sensitive: true */
for (var i = 0; i < 0x1337b33f; i++) {
  heapSprayChunk("AAAAA");
}
/* jsobfu memory_sensitive: false */
/* jsobfu enabled: false */
// this comment will be in the output
/* jsobfu enabled: true */
// this comment will not.

[joevennix]

This turns out to be very hard to implement. Rkelly throws away context-specific details about comments (it preserves line number and char, but these are not so useful in a visitor-based transformer). The best plan I can think of (e.g., that does not involve adding a ton of edge cases everywhere) would involve forking rkelly and making it treat comments like a syntax node.