std::string vs. ePub3::string .size() methods must be used carefully when dealing with .c_str() raw char buffers (see ePub3::string .utfsize() or strlen(charbuf)).
The fixes in this commit address *only* the routines that handle percent-escape decoding.
Merge pull request #142 from readium/feature/utfStringSize

std::string vs. ePub3::string .size() methods