Add support for keys with nested dots.

Through modifications to `doc-path` and `deeks` dependency underlying
code, I've worked to add support for the keys with nested dots in the
JSON key path and conversion back to CSV. This was achieved through the
`deeks` module's new `escapeNestedDots` option which will now be set to
`true`. Additionally, support for this escaping was added to `doc-path`
so that the correct values are retrieved and can also be correctly set
for csv2json. This commit adds the option specification for the `deeks`
module, and once the dependency modules are released, another commit
will be pushed which will update the dependency module versions to the
newest releases which add support.

Fixes #184

lib/json2csv.js

@@ -12,7 +12,8 @@ const Json2Csv = function(options) {
         expandingWithoutUnwinding = options.expandArrayObjects && !options.unwindArrays,
         deeksOptions = {
             expandArrayObjects: expandingWithoutUnwinding,
-            ignoreEmptyArraysWhenExpanding: expandingWithoutUnwinding
+            ignoreEmptyArraysWhenExpanding: expandingWithoutUnwinding,
+            escapeNestedDots: true
         };
 
     /** HEADER FIELD FUNCTIONS **/