v8.1.0

#220 Create a BigNumber using {s, e, c}.
isBigNumber: if BigNumber.DEBUG is true, also check that the BigNumber instance is well-formed.
Remove instanceof checks; just use _isBigNumber to identify a BigNumber instance.
Add _isBigNumber to prototype in bignumber.mjs.
Add tests for BigNumber creation from object.
Update typescript definitions: make BigNumber.Instance an interface.
Add tests for BigNumber creation from object.
Update API.html.

v8.1.0

#220 Create a BigNumber using {s, e, c}.
isBigNumber: if BigNumber.DEBUG is true, also check that the BigNumber instance is well-formed.
Remove instanceof checks; just use _isBigNumber to identify a BigNumber instance.
Add _isBigNumber to prototype in bignumber.mjs.
Add tests for BigNumber creation from object.
Update typescript definitions: make BigNumber.Instance an interface.
Add tests for BigNumber creation from object.
Update API.html.