Janet 1.7.0

Many new functions and macros that should be generally useful, like assert and eachk. There is some backwards incompatibility in the Janet core with the removal of the numeric operators (==, not==, etc), removal of the emscripten build, removal of file/fileno and file/fdopen, and some changes to comparison functionality for abstract types. Many other small changes in the Changelog.

• Remove file/fileno and file/fdopen.
• Remove ==, not==, order<, order>, order<=, and order>=. Instead, use the normal
  comparison and equality functions.
• Let abstract types define a hash function and comparison/equality semantics. This lets
  abstract types much better represent value types. This adds more fields to abstract types, which
  will generate warnings when compiled against other versions.
• Remove Emscripten build. Instead, use the amalgamated source code with a custom toolchain.
• Update documentation.
• Add var-
• Add module/add-paths
• Add file/temp
• Add mod function to core.
• Small bug fixes
• Allow signaling from C functions (yielding) via janet_signalv. This
  makes it easy to write C functions that work with event loops, such as
  in libuv or embedded in a game.
• Add '%j' formatting option to the format family of functions.
• Add defer
• Add assert
• Add when-with
• Add if-with
• Add completion to the default repl based on currently defined bindings. Also generally improve
  the repl keybindings.
• Add eachk
• Add eachp
• Improve functionality of the next function. next now works on many different
  types, not just tables and structs. This allows for more generic data processing.
• Fix thread module issue where sometimes decoding a message failed.
• Fix segfault regression when macros are called with bad arity.