XamlViewer Versions Save

1. Support singleton application;
2. Fix #8;
3. Save data source to independent file;
4. Other optimizations.

1. Support json as data source;
2. Support cursor position indicator for ruler;
3. New title style of unsaved file;
4. Add data source example
5. Fix fuzzy snapshot;
6. Other bug fixs and optimizations.

1. Support multi-target framework (.Net Core 3.1 and .Net Framework 4.5);
2. Other bug fixs.

1. Support dragging files to open;
2. Show total downloads of latest version;
3. Support catching global unhandled exception;
4. Modified animation example;
5. Other bug fixs.

1. New help page;
2. Add some examples;
3. Fix the occasional problem of dragging tabs;
4. Support for detecting new release;

1. Optimize the “Code Completion”;
2. Fixed issue with adding third-party references;
3. Remove "Line Number" and add "Code Completion" setting.

1. Each document has its own independent editor and designer;
2. Add "Snapshot to file";
3. Fix auto save problem while closing;
4. Modify some icons;
5. Other optimizations;

1. add some missing elements in intellisense
2. modify logo
3. other optimizations

Release 1.0