RCORE: fix RAPICORN_ABS() to also work with unsigned types
RCORE: rename RAPICORN_NOINLINE
RCORE: document Lib namespace as internal
RCORE: add Lib::StringFormatter for type safe printf-like formatting
RCORE: add string_format() for type safe printf-like formatting
RCORE: add string_locale_format()
RCORE: strings: use string_format instead of printf variants
RCORE: fixup string_hexdump() and add test case
RCORE: move arg assignments into StringFormatter::assign
RCORE: StringFormatter: ensure to keep copies to temporary sstream strings around
RCORE: test ostream operator<< support for string_format()
RCORE: StringFormatter: pass all format arguments as const&
RCORE: use type safe string_locale_printf<>() and string_printf<>() everywhere
RCORE: add comments about finding strings with size modifiers
RCORE: StringFormatter: properly handle "%%" sequences
RCORE: utilities.hh: comment fixup
Merge branch 'string-formatter'

* string-formatter:
  RCORE: utilities.hh: comment fixup
  RCORE: StringFormatter: properly handle "%%" sequences
  RCORE: add comments about finding strings with size modifiers
  RCORE: use type safe string_locale_printf<>() and string_printf<>() everywhere
  RCORE: StringFormatter: pass all format arguments as const&
  RCORE: test ostream operator<< support for string_format()
  RCORE: StringFormatter: ensure to keep copies to temporary sstream strings around
  RCORE: move arg assignments into StringFormatter::assign
  RCORE: fixup string_hexdump() and add test case
  RCORE: strings: use string_format instead of printf variants
  RCORE: add string_locale_format()
  RCORE: add string_format() for type safe printf-like formatting
  RCORE: add Lib::StringFormatter for type safe printf-like formatting
  RCORE: document Lib namespace as internal
  RCORE: rename RAPICORN_NOINLINE
  RCORE: fix RAPICORN_ABS() to also work with unsigned types