Introduce PEEK command.

Peek at arbitrary resumes and resume objects paths with "hackmyresume
peek <resume> [objectPath]". For ex:

hackmyresume PEEK resume.json
hackmyresume PEEK resume.json info
hackmyresume PEEK resume.json employment[2].keywords
hackmyresume PEEK r1.json r2.json r3.json info.brief

src/core/event-codes.js

@@ -32,7 +32,9 @@ Event code definitions.
     afterConvert:     16,
     verifyOutputs:    17,
     beforeParse:      18,
-    afterParse:       19
+    afterParse:       19,
+    beforePeek:       20,
+    afterPeek:        21
   };