Update unicorn version to 1.0.3

[smeng9]

This PR updates unicorn to latest version with all the bug fixes.

Additionally, it:
Update the build instructions on README as old Python 2.x and emsdk 1.x are deprecated
Fix build scripts as some of the build arguments get changed
Update unicorn wrapper as some use strict JavaScript mode throws error about two unused function argument uses the same _ as place holder

[AlexAltea]

Awesome, thank you @smeng9! Have you tested Unicorn.js after the changes?

[smeng9]

Yes, I have recompiled it and it seems worked fine on my end.

…

________________________________ From: Alexandro Sanchez ***@***.***> Sent: Monday, May 31, 2021 6:03 AM To: AlexAltea/unicorn.js ***@***.***> Cc: Meng, Shaoyu ***@***.***>; Mention ***@***.***> Subject: Re: [AlexAltea/unicorn.js] Update unicorn version to 1.0.3 (#28) Awesome, thank you @smeng9<https://urldefense.com/v3/__https://github.com/smeng9__;!!DZ3fjg!tFUxCRdfP71TJitsgSDmoBOh6y9GqaIdreU5DE7xs6ue7ayAf34Hb3Q420ehYL90hA$>! Have you tested Unicorn.js after the changes? — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub<https://urldefense.com/v3/__https://github.com/AlexAltea/unicorn.js/pull/28*issuecomment-851410529__;Iw!!DZ3fjg!tFUxCRdfP71TJitsgSDmoBOh6y9GqaIdreU5DE7xs6ue7ayAf34Hb3Q420cIEbPmEQ$>, or unsubscribe<https://urldefense.com/v3/__https://github.com/notifications/unsubscribe-auth/AJHAEC3TKNON7E2A65ETR6LTQNUHZANCNFSM45VXZVZA__;!!DZ3fjg!tFUxCRdfP71TJitsgSDmoBOh6y9GqaIdreU5DE7xs6ue7ayAf34Hb3Q420fx5k8dGg$>.

[AlexAltea]

Great, thank you very much!