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, 29 insertions, 0 deletions

diff --git a/lang/js/.eslintrc.json b/lang/js/.eslintrc.json
new file mode 100644
index 00000000..65253cf3
--- /dev/null
+++ b/lang/js/.eslintrc.json
@@ -0,0 +1,29 @@
+{
+    "env": {
+        "browser": true,
+        "es6": true
+    },
+    "extends": "eslint:recommended",
+    "parserOptions": {
+        "sourceType": "module"
+    },
+    "rules": {
+        "indent": [
+            "warn",
+            4
+        ],
+        "linebreak-style": [
+            "error",
+            "unix"
+        ],
+        "quotes": [
+            "error",
+            "single"
+        ],
+        "semi": [
+            "error",
+            "always"
+        ],
+        "max-len": 1
+    }
+}
\ No newline at end of file