Updated build script and nuspec file for 0.8.4-rc1

Author: marto83

default.ps1

@@ -10,7 +10,7 @@ properties {
 	$sln_name = "IO.Ably.sln"
 
 	$project_name = "IO.Ably"
-	$build_number = "0.8.3"
+	$build_number = "0.8.4"
 	$solution_dir = "$build_script_dir\$sln_dir"
 
 	$build_artifacts_dir_base = "$build_script_dir\build\artifacts"

nuget/io.ably.nuspec

@@ -2,7 +2,7 @@
 <package xmlns="http://schemas.microsoft.com/packaging/2012/06/nuspec.xsd">
     <metadata>
         <id>ably.io</id>
-        <version>0.8.3</version>
+        <version>0.8.4-rc1</version>
         <title>ably.io</title>
         <authors>Yavor Ivanov,Martin Georgiev</authors>
         <owners>Ably Real-time Ltd</owners>