remove unecessary version guard

[Firescar96]

This guard is making it impossible for developers to use this library without various hacks. I've seen a few complaints about it as well as hacky solutions to bypass it.

https://github.com/bitpay/bitcore-lib/search?q=versionGuard&type=Issues&utf8=✓
https://stackoverflow.com/questions/46315459/bitcore-more-than-one-instance-of-bitcore-lib-found
https://forum.bitcore.io/t/more-than-one-instance-of-bitcore-lib-found/699
https://stackoverflow.com/questions/45217988/error-more-than-one-instance-of-library-found
https://bitcoin.stackexchange.com/questions/46795/bitcore-error-more-than-one-instance-of-bitcore-lib-found
https://stackoverflow.com/questions/47010584/nodejs-eth-lightwallet-doesnt-allow-different-bitcore-lib-versions-among-submod
https://forum.bitcore.io/t/error-more-than-one-instance-of-bitcore-lib-found-please-make-sure-to-require-bitcore-lib-and-check-that-submodules-do-not-also-include-their-own-bitcore-lib-dependency/1612

Some of these issues were even marked as high priority, before being closed with the resolution as a hacky solution:

bitpay/bitcore#1454
bitpay/bitcore#1484
bitpay/bitcore#1328
bitpay/bitcore#1366
bitpay/bitcore#1486
bitpay/bitcore#1453
bitpay/bitcore#1454
bitpay/bitcore#1457
bitpay/bitcore#1232
bitpay/bitcore#1303
bitpay/bitcore#1144

#153
#67
bitpay/bitcore#1366
bitpay/bitcore#1232
bitpay/bitcore#1457
bitpay/bitcore-mnemonic#26
bitpay/bitcore-mnemonic#58
bitpay/i-made-this#15
bitpay/bitcore-wallet-service#643

People are just using delete global._bitcore or other hacks so this code is doing more harm than good.

[Firescar96]

@matiu all the tests pass, are there other errors caused by deleting this code?

[fanatid]

@Firescar96 you can not just remove version guard without any other changes.
You need remove all instanceof calls (nearly 50 calls in lib) first.

[Firescar96]

I'm not sure what the version guard has to do with calls to instanceof. Calls like these?
https://github.com/bitpay/bitcore-lib/blob/484683f854ad8bcac8a5b0e197d5704f80ebdae6/lib/crypto/ecdsa.js

bitcore-lib/test/hdpublickey.js

Line 122 in ed02685

expect(a instanceof b).to.equal(true);

[fanatid]

@Firescar96 please check bitpay/bitcore#1164 bitpay/bitcore#1165

[Firescar96]

I see. Another suggestion I saw was to make bitcore-lib a peer dependency. Looking at the releases NPM has supported peer dependencies for a couple years.

Would a solution be to do this for all of bitpay's other libraries, bitcore, bitcore-mnemonic, etc?

[Firescar96]

closing this, bitpay/bitcore-mnemonic#61 is a replacement