Automattic local caching / saving of music; Local red heart channel; solved a bug on JSON

Hey hzqtc, There are loads of changes maded in my fork so maybe you'd want to take a look.

To enable caching and music saving I've done quite a bit of hacking and tinkering, and I'm guessing that part is not what you want to include in your original repo. 

However, I noticed a bug in you fmd such that a double quote in some property of the song would potentially corrupt the output of 'info' command and consequently cause a segmentation fault in fmc. So probably you'd want to fix that like I've already done.