jsonstream renovation

add inline on inline function in header (would be link error)
  restore ostream's flags in jsonstream destructor
  char, char16_t, and char32_t are not treated as integers
    (signed char and unsigned char are)
  use [=] in lambdas for small values
  eliminate need for json_stream.cc through creative enum use
  change "x" to 'x' in ostream <<
  reduce object bloat by making transition() call non-template _transition()
  merge duplicated code in _transition()