New Note from Selection, Package markdownit dependency

Enhancements:

• #96 option to disable lower-casing of file names - tx @mgmeyers
• #95 vscodeMarkdownNotes.newNoteFromSelection which will "cut" the selected text from the current document, prompt for a note name, create a new note with that name, and insert the new text into that note. tx @mgmeyers

Fixes:

• #104 package missing markdown it dependency in production build - tx @Lemmingh

Diff:

https://github.com/kortina/vscode-markdown-notes/compare/431084c..4d315eb