Refactor xcode version (xcode 9 support) and dependencies update. (#2)

* refactor project and dependencies, version bump

* update podspec and version

Author: dev-mush

Example/Podfile.lock

@@ -1,20 +1,20 @@
 PODS:
   - jrpc (0.1.0-beta)
-  - OHHTTPStubs (5.2.3):
-    - OHHTTPStubs/Default (= 5.2.3)
-  - OHHTTPStubs/Core (5.2.3)
-  - OHHTTPStubs/Default (5.2.3):
+  - OHHTTPStubs (6.0.0):
+    - OHHTTPStubs/Default (= 6.0.0)
+  - OHHTTPStubs/Core (6.0.0)
+  - OHHTTPStubs/Default (6.0.0):
     - OHHTTPStubs/Core
     - OHHTTPStubs/JSON
     - OHHTTPStubs/NSURLSession
     - OHHTTPStubs/OHPathHelpers
-  - OHHTTPStubs/JSON (5.2.3):
+  - OHHTTPStubs/JSON (6.0.0):
     - OHHTTPStubs/Core
-  - OHHTTPStubs/NSURLSession (5.2.3):
-    - OHHTTPStubs/Core
-  - OHHTTPStubs/OHPathHelpers (5.2.3)
-  - OHHTTPStubs/Swift (5.2.3):
+  - OHHTTPStubs/NSURLSession (6.0.0):
     - OHHTTPStubs/Core
+  - OHHTTPStubs/OHPathHelpers (6.0.0)
+  - OHHTTPStubs/Swift (6.0.0):
+    - OHHTTPStubs/Default
 
 DEPENDENCIES:
   - jrpc (from `../`)
@@ -23,12 +23,12 @@ DEPENDENCIES:
 
 EXTERNAL SOURCES:
   jrpc:
-    :path: "../"
+    :path: ../
 
 SPEC CHECKSUMS:
   jrpc: 18809df6734648427b9a198463038dababeaf7f3
-  OHHTTPStubs: e238cd5b66d8efa51c861db45895de8fe079f4a7
+  OHHTTPStubs: 752f9b11fd810a15162d50f11c06ff94f8e012eb
 
 PODFILE CHECKSUM: 3690747f8d520720be55b3acc0aff0bee999b55f
 
-COCOAPODS: 1.2.0
+COCOAPODS: 1.3.1