Documentation for v1.3.15

[CrashTestJava]

Documentation for v1.3.15:

• Add docs for onchecked parameter to plugin:newCommand()
• Add docs for resizeable parameter to dialog constructor
• Add docs for mouseCursor parameter in dialog.md
• Add docs for sprite.id
• Add docs for sprite.colorSpace
• Add docs for sprite.undoHistory
• Add codeblock for sprite.colorMode

Documentation for v1.3.14.3:

• Add app.clipboard to app.md
• Add docs for sprite events: filenamechange, blendMode, name, opacity and visibility

Misc:

• Update Changes.md
• Add docs for ondblclick event for canvas events
• Add FlipType to sidebar and readme
• Fix minor issues and typos

Closes:
#132
#131
#129
#128