refactor: remove AbstractResume base class

(1) AbstractResume adds complexity without contributing utility. There's not
really a clean "class" abstraction in JavaScript to begin with; CoffeeScript
classes, as nice as they are syntactically, occlude the issue even further.

(2) AbstractResume currently functions as a container for exactly two functions
which arguably should live outside the resume class anyway.

dist/inspectors/duration-inspector.js

@@ -0,0 +1,56 @@
+(function() {
+  var FluentDate, _;
+
+  FluentDate = require('../core/fluent-date');
+
+  _ = require('underscore');
+
+  module.exports = {
+
+    /**
+    Compute the total duration of the work history.
+    @returns The total duration of the sheet's work history, that is, the number
+    of years between the start date of the earliest job on the resume and the
+    *latest end date of all jobs in the work history*. This last condition is for
+    sheets that have overlapping jobs.
+     */
+    run: function(rez, collKey, startKey, endKey, unit) {
+      var firstDate, hist, lastDate, new_e;
+      unit = unit || 'years';
+      hist = __.get(rez, collKey);
+      if (!hist || !hist.length) {
+        return 0;
+      }
+      new_e = hist.map(function(job) {
+        var obj;
+        obj = _.pick(job, [startKey, endKey]);
+        if (!_.has(obj, endKey)) {
+          obj[endKey] = 'current';
+        }
+        if (obj && (obj[startKey] || obj[endKey])) {
+          obj = _.pairs(obj);
+          obj[0][1] = FluentDate.fmt(obj[0][1]);
+          if (obj.length > 1) {
+            obj[1][1] = FluentDate.fmt(obj[1][1]);
+          }
+        }
+        return obj;
+      });
+      new_e = _.filter(_.flatten(new_e, true), function(v) {
+        return v && v.length && v[0] && v[0].length;
+      });
+      if (!new_e || !new_e.length) {
+        return 0;
+      }
+      new_e = _.sortBy(new_e, function(elem) {
+        return elem[1].unix();
+      });
+      firstDate = _.first(new_e)[1];
+      lastDate = _.last(new_e)[1];
+      return lastDate.diff(firstDate, unit);
+    }
+  };
+
+}).call(this);
+
+//# sourceMappingURL=duration-inspector.js.map