More elegant multi-screen support

[Harry-Chen]

Some ideas:

• Allow selecting monitors to display on when starting
• Allow displaying on a specific area instead of the whole screen

[Harry-Chen]

This issue is inspired by #19 .

[Changkey]

Sounds nice.Now I wonder when to release a Windows application.

[Harry-Chen]

@Changkey There will be a Window release when bumping to 0.2.3. Please wait a few more days.

[Harry-Chen]

@Changkey version 0.2.3 has been released now.