Files without extensions are not correctly handled

[tmbenhura]

Tested Versions: 0.15.0 and 0.22.0

Files without extensions do not seem to trigger matchers.

Whilst debugging, in matchers.py I added

print("Content:" + str(att.has_content) + " Signature:" + str(att.has_magic_signature(b'%PDF')))
I get:
Content:False Signature:False Content:False Signature:False

Yet the PDF has content and starts with %PDF. It is also printed twice, not sure why.

[MaximeRivest]

Thanks printed twice should be fix will look into the no extension issue soon