Add PCL Profile7 build for SS.Text

Author: mythz

src/ServiceStack.Text/project.json

@@ -2,12 +2,17 @@
   "configurations": {
     "Debug": {
       "buildOptions": {
-        "define": [ "DEBUG", "TRACE" ]
+        "define": [
+          "DEBUG",
+          "TRACE"
+        ]
       }
     },
     "Release": {
       "buildOptions": {
-        "define": [ "TRACE" ],
+        "define": [
+          "TRACE"
+        ],
         "optimize": true
       }
     }
@@ -25,6 +30,20 @@
         "Microsoft.CSharp": "4.0.1-*",
         "System.Reflection.Emit": "4.0.1"
       }
+    },
+    ".NETPortable,Version=v4.5,Profile=Profile7": {
+      "buildOptions": {
+        "define": [
+          "PCL"
+        ]
+      },
+      "frameworkAssemblies": {
+        "System.Runtime.Serialization.Primitives": "4.1.1-*",
+        "System.Runtime.Serialization.Xml": "4.1.1",
+        "System.Net.Requests": "4.0.11",
+        "System.Dynamic.Runtime": "4.0.11",
+        "Microsoft.CSharp": "4.0.1-*"
+      }
     }
   },
   "version": "1.0.0"