Public release of the MvsSln - v2.1

* FIXED: Fixed bug 'The node is not parented by this object'
         When IXProject.RemoveImport is used for `Import` elements inside `ImportGroup`.
         Related issue: 3F/DllExport#77

* NEW: Added `IXProject.AddImport(IEnumerable<ImportElement> elements, ...`
       To add 'import' elements inside ImportGroup.

* CHANGED: IXProject changes:
    * +`IXProject.PId` an unique identifier for project (not instance).
    * +`IXProject.GetRelativePath(string path)` Makes relative path from used project.
    * +`IXProject.AddImport(ImportElement element);`
    * Compatible signature update: `bool RemoveImport(ImportElement element, bool holdEmptyGroup = false)`

* CHANGED: Additional .ctors for XProject:
    * +`XProject()`
    * +`XProject(string file)`
    * +`XProject(string file, IDictionary<string, string> properties)`
    * +`XProject(Project prj)`

.version

@@ -1 +1 @@
-2.0.0
+2.1.0

Readme.md

@@ -285,4 +285,4 @@ Available variants:
 
 ## &_
 
-[![Donate](https://www.paypalobjects.com/en_US/i/btn/btn_donate_SM.gif)](https://www.paypal.com/cgi-bin/webscr?cmd=_donations&business=entry%2ereg%40gmail%2ecom&lc=US&item_name=3F%2dOpenSource%20%5b%20github%2ecom%2f3F&currency_code=USD&bn=PP%2dDonationsBF%3abtn_donate_SM%2egif%3aNonHosted)
+[![Donate](https://www.paypalobjects.com/en_US/i/btn/btn_donate_SM.gif)](https://r-eg.net/Donation/)

changelog.txt

@@ -2,6 +2,26 @@
 MvsSln  :: https://github.com/3F/MvsSln
 _ _ _ _
 
+[v2.1] 2018.08.05
+
+    * FIXED: Fixed bug 'The node is not parented by this object' 
+             When IXProject.RemoveImport is used for `Import` elements inside `ImportGroup`.
+             Related issue: https://github.com/3F/DllExport/issues/77
+
+    * NEW: Added `IXProject.AddImport(IEnumerable<ImportElement> elements, ...` 
+           To add 'import' elements inside ImportGroup.
+
+    * CHANGED: IXProject changes:
+        * +`IXProject.PId` an unique identifier for project (not instance).
+        * +`IXProject.GetRelativePath(string path)` Makes relative path from used project.
+        * +`IXProject.AddImport(ImportElement element);`
+        * Compatible signature update: `bool RemoveImport(ImportElement element, bool holdEmptyGroup = false)`
+
+    * CHANGED: Additional .ctors for XProject:
+        * +`XProject()`
+        * +`XProject(string file)`
+        * +`XProject(string file, IDictionary<string, string> properties)`
+        * +`XProject(Project prj)`
 
 [v2.0] 2017.10.05