Replace 128 (the ID3v1 tag length) with a named constant for clarity.
Merge pull request #33 from robertyseward/tag-length

Replace 128 with a named constant
Move the stats cache code into its own file.

Change the stats cache size to be in number of entries instead of bytes.

Don't use 'using std::'.  As part of this, typedef some 'std::' things to
make the code more readable.

Put static variables in an unnamed namespace instead of using 'static'.
Merge branch 'master' of https://github.com/khenriks/mp3fs

Conflicts:
	src/mp3_encoder.cc
	src/mp3_encoder.h
	src/transcode.cc
Move a static function to an unnamed namespace.