js: implement import/delete Key, some fixes

--

* Keyring.js
   - implemented importKey: importing one or more armored public key
     blocks.
   - implemented deleteKey: deleting a public Key from gpg.

* Key.js renamed property Key.armor to Key.armored

* Helpers.js: toKeyIDArray does not complain anymore if there are no
  keys. Not having Keys in e.g. signing keys in encrypt is legitimate
  and common, the complaints were getting spammy

* Errors.js: gpgme_errors now always pass an optional additional
  message, for easier debugging in minified code

* Connection.js: Fix in gpgme-json responses containing objects

* eslintrc.json: Start using eslint. A cleanup to conform to it is not
  done yet

* Added further tests for the new functionality

1 files changed, 3 insertions, 2 deletions

diff --git a/lang/js/src/Connection.js b/lang/js/src/Connection.js
index 3480d811..8c4cba7c 100644
--- a/lang/js/src/Connection.js
+++ b/lang/js/src/Connection.js
@@ -103,7 +103,7 @@ export class Connection{
         }
         if (!message || !message instanceof GPGME_Message){
             this.disconnect();
-            return Promise.reject(gpgme_error('PARAM_WRONG'), message);
+            return Promise.reject(gpgme_error('PARAM_WRONG', 'Connection.post'));
         }
         if (message.isComplete !== true){
             this.disconnect();
@@ -221,12 +221,13 @@ class Answer{
                         if (!this._response.hasOwnProperty(key)){
                             this._response[key] = [];
                         }
+
                         if (Array.isArray(msg[key])) {
                             for (let i=0; i< msg[key].length; i++) {
                                 this._response[key].push(msg[key][i]);
                             }
                         } else {
-                            this._response[key].push(msg[key][i]);
+                            this._response[key].push(msg[key]);
                         }
                     }
                     else {