Small fixes
Manage planet::filesystem with unique_ptr
tcp.data: fdsets should not be static
fill_st_inode: temporary way to fix a weird bug

 In fill_st_inode(), valgrind reports an invalid read
at fuse_get_context()->gid.
 So instead of that we temporarily use getgid().
unlink: remove a file if no operations to unlink found
request_parser: fix bug passing a temporary string to regex_match()
Forgot to commit exception.hpp
Merge branch 'develop'

This merge includes:
 * fix various errors of `invalid read` reported by valgrind
 * other trivial fixes