ZK Audio component use source URL for content type recognition instead of Content-Type HTTP header.

Steps to reproduce:
1. Set audio tag src="http://localhost/rest/stream/"
2. Create web service returning for REST GET /rest/stream:

HTTP/1.1 206
Accept-Ranges: bytes
Content-Range: bytes 0-8044543/10266064
Last-Modified: Sat, 17 Nov 2018 21:29:04 GMT
Content-Type: audio/mpeg
Content-Length: 8044544
Date: Sat, 17 Nov 2018 21:29:06 GMT

3. Open zul with such video tag in browser.

Actual result:
video tag set type="audio/wav". audio is not playing

Expected result:
video tag should set type="audio/mpeg"