Suggestion: some changes in String API (and source compatibility between TagLib 1 and 2)

[Tsuda Kageyu]

Scott brought up three options:

>- Try to preserve source compatibility for common cases, making porting 
>from TagLib 1 to TagLib 2 as easy as possible
>
>- Allow all API cleanups now since TagLib 1 is now almost 10 years old 
>and the TagLib 1 to 2 transition will be the last chance for API 
>breakage for probably a very long time
>
>- Do like Qt often does in major version changes and include 
>compatibility functions in the API that are marked as deprecated.

My opinion is similar to the first one. But I just want to fix a small 
number of things confusing for users (especially new users like me). I 
think that TagLib is well-designed library as a whole, so I have no 
intention to redesign its API thoroughly. I'm not afraid of breaking the 
source compatibility between TagLib 1 and 2, but also think that the 
change should be easily understandable for existing users.

Kageyu.