Update nuspec (#41)

Author: josesimoes

source/nanoFramework.Networking.Sntp.nuspec

@@ -7,11 +7,13 @@
     <authors>nanoFramework project contributors</authors>
     <owners>nanoFramework project contributors</owners>
     <requireLicenseAcceptance>false</requireLicenseAcceptance>
+    <license type="expression">Apache-2.0</license>
     <releaseNotes>
     </releaseNotes>
     <developmentDependency>false</developmentDependency>
     <projectUrl>https://github.com/nanoframework/lib-nanoFramework.Networking.Sntp</projectUrl>
     <iconUrl>https://secure.gravatar.com/avatar/97d0e092247f0716db6d4b47b7d1d1ad</iconUrl>
+    <repository type="git" url="https://github.com/nanoframework/lib-nanoFramework.Networking.Sntp" commit="$commit$" />
     <copyright>Copyright (c) 2018 The nanoFramework project contributors</copyright>
     <description>This package includes the nanoFramework.Networking.Sntp assembly for nanoFramework C# projects.</description>
     <summary>nanoFramework.Networking.Sntp assembly for nanoFramework C# projects</summary>
@@ -26,5 +28,8 @@
     <file src="nanoFramework.Networking.Sntp\bin\Release\nanoFramework.Networking.Sntp.pdbx" target="lib\nanoFramework.Networking.Sntp.pdbx" />
     <file src="nanoFramework.Networking.Sntp\bin\Release\nanoFramework.Networking.Sntp.pe" target="lib\nanoFramework.Networking.Sntp.pe" />
     <file src="nanoFramework.Networking.Sntp\bin\Release\nanoFramework.Networking.Sntp.xml" target="lib\nanoFramework.Networking.Sntp.xml" />
+
+    <!-- readme -->
+    <file src="readme.txt" target="readme.txt" />
   </files>
 </package>

source/readme.txt

@@ -0,0 +1,21 @@
+                         _____                                            _    
+   _ __   __ _ _ __   ___ |  ___| __ __ _ _ __ ___   _____      _____  _ __| | __
+  | '_ \ / _` | '_ \ / _ \| |_ | '__/ _` | '_ ` _ \ / _ \ \ /\ / / _ \| '__| |/ /
+  | | | | (_| | | | | (_) |  _|| | | (_| | | | | | |  __/\ V  V / (_) | |  |   < 
+  |_| |_|\__,_|_| |_|\___/|_|  |_|  \__,_|_| |_| |_|\___| \_/\_/ \___/|_|  |_|\_\
+                                                                               
+===================================================================================
+
+API docs: https://docs.nanoframework.net/api/nanoFramework.Networking.Sntp.html
+
+Browse our samples repository: https://github.com/nanoframework/samples
+
+Check our documentation online: https://docs.nanoframework.net/articles/intro.html
+
+Join our lively Discord community: https://discord.gg/gCyBu8T
+
+Report issues: https://github.com/nanoframework/Home/issues
+
+Follow us on Twitter: https://twitter.com/nanoframework
+
+Follow our YouTube channel: https://www.youtube.com/c/nanoFramework