v0.6.1 update

[matyalatte]

New features

• Added radio buttons to GUI components

Bug fixes

• Fixed an error when opening URLs with debug builds.
• Fixed a crash when the executed process uses multiprocessing on Windows.
• Fixed a bug that drag-drop events are ignored on newer versions of GTK.
• Fixed a bug that tuw didn't check the type of the "default" values for combo boxies.

Docs updates

"placeholder" and "combo" are already supported as alternate spellings in old versions. I decided to use them as the standard ones.

• Replaced "empty_message" with "placeholder" in docs.
• Replaced "choice" with "combo" in docs.