Change name of default Tab/File name at startup of multi-tab editor

[DeeJay]

Is your feature request related to a problem? Please describe.
I am liking what is emerging with the multi-tab editor interface.

But 'test.py' seems a non-intuitive choice of initial default tab name. It does not represent a file actually present in the filesystem.

Describe the solution you'd like
Making it a Markdown file - which by default cannot be editted - might make it clearer that this Startup tab is different.
"README.md"

Describe alternatives you've considered
Alternatively a self-documenting tab/file name such as 'ViperIDE_Intro.py"

Additional context
This is purely cosmetic and does not affect the functioning of the IDE.

The change is probably needed at around L 1146 of src/app.js