Suggestion: Removal of "AudioProperties::ReadStyle" enumeration

[Tsuda Kageyu]

Hi.
I suggest to remove "AudioProperties::ReadStyle" enumeration and 
"propertiesStyle" parameter of "File" constructors from TagLib2.0.

This is because they are seldom used. As a matter of fact, only WavPack 
care about the parameter and all other formats ignore it. It gives users 
the impression that it affects the reading process of files against the 
fact.

IMO, for the above reasons, they are virtually meaningless and even 
misleading for users. I want to hear someone's opinion.

Kageyu.