Internet Explorer (pre-Edge) fails to load sxc v3.3.0-beta.1 (Object.assign is not available)

[SproulDog]

Some feedback for v3.3.0-beta.1 (thanks)

Expected behavior

In current releases, IE browsers work as expected (and even beyond) without WebRTC. ie: Chat functions work fine.

Actual behavior

v3.3.0-beta.1 includes some additional references to Onject.assign (which is not available in IE-PreEdge). and therefore prevents JSXC from loading/functioning. As best I can tell, a small newly refactored code block has been introduced and this is causing the exception (and follow on effects).

Steps to reproduce the behavior

1. Attempt to use the mentioned beta release with IE 11 or earlier

Environment

• **JSXC version: v3.3.0-beta.1
• **Host system and version: Any (Windows 8, etc)
• Browser vendor and version: IE Pre-Edge
• **Any browser plugins enabled? N/A
• *XMPP server vendor and version: N/A
• **Is your XMPP server working with other clients as expected? Yes

Logs

jsxc v3.3.0-beta.1 - 2017-07-27
....\jsxc\lib\jsxc.dep.js(38122):

// Shimming starts here.
...
 var options = Object.assign({ <---Object.Assign is not available on ie-pre edge
    shimChrome: true,
    shimFirefox: true,
    shimEdge: true,
    shimSafari: true,
  }, opts);

The effect is that jsxc will not raise an exception (and will fail to load) on Internet Explorer (Pre-Edge).

[sualko]

I think it's the same issue as in #584 and it was probably fixed in the third-party library. I will update and include it in the next beta release. Thanks for pointing this out.