v2.2

Public release of MvsSln - v2.2

* FIXED: Fixed possible error when loading all found projects:
        'An equivalent project is already present in the project collection, ...'

* NEW: Implemented R/W Handlers for `NestedProjects` section. Issue #7

* NEW: Implemented new R/W handlers for `ExtensibilityGlobals` section.
        Use `ExtItems = 0x0400` flag to activate it.

* NEW: Implemented native object comparison for ProjectItem, SolutionFolder, and RawText.
        ```
        ~
        if(new ProjectItem(...) == new ProjectItem(...)) { ... }
        if(new SolutionFolder(...) == new SolutionFolder(...)) { ... }
        if(new RawText(...) == new RawText(...)) { ... }
        if(new ConfigItem(...) == new ConfigItem(...)) { ... }
        if((RawText)"data" == (RawText)"data") { ... }
        ```

* NEW: New constructors for `SolutionFolder`. Issue #8:
    ```
    +SolutionFolder(string fGuid, string name, IEnumerable<RawText> items)
    +SolutionFolder(Guid fGuid, string name)
    +SolutionFolder(string fGuid, string name, SolutionFolder parent, params RawText[] items)
    +SolutionFolder(string fGuid, string name, SolutionFolder? parent, IEnumerable<RawText> items)
    +SolutionFolder(string name, params RawText[] items)
    +SolutionFolder(string name, IEnumerable<RawText> items)
    +SolutionFolder(string name, SolutionFolder parent, params RawText[] items)
    +SolutionFolder(string name, SolutionFolder parent, IEnumerable<RawText> items)
    +SolutionFolder(ProjectItem pItem, params RawText[] def)
    +SolutionFolder(SolutionFolder folder)
    ```

* NEW: New constructors for `ProjectItem` (part of Issue #8):
    ```
    +ProjectItem(string name, ProjectType pType, SolutionFolder? parent = null)
    +ProjectItem(string name, ProjectType pType, string path, SolutionFolder? parent = null, string slnDir = null)
    +ProjectItem(string pGuid, string name, ProjectType pType, SolutionFolder? parent = null)
    +ProjectItem(string pGuid, string name, ProjectType pType, string path, SolutionFolder? parent = null, string slnDir = null)
    +ProjectItem(string pGuid, string name, string path, string pType, string slnDir = null)
    +ProjectItem(ProjectItem prj)
    ```

* CHANGED: `ProjectItem.ProjectTypeBy(string guid)` marked as [Obsolete] and can be removed in new versions later.
            You can use new methods when you need:
            * `Guids.ProjectTypeBy(string guid)`
            * `Guids.GuidBy(ProjectType type)`

* CHANGED: Updated package tools hMSBuild 2.0 & GetNuTool 1.7.
           Release notes:
            * https://github.com/3F/GetNuTool/releases/tag/v1.7
            * https://github.com/3F/hMSBuild/releases/tag/v2.0