Get rid of the separate opt-in IO class and replace it with a core
System class.
- Remove wren_io.c, wren_io.h, and io.wren.
- Remove the flags that disable it.
- Remove the overloads for print() with different arity. (It was an
experiment, but I don't think it's that useful.)
- Remove IO.read(). That will reappear using libuv in the CLI at some
point.
- Remove IO.time. Doesn't seem to have been used.
- Update all of the tests, docs, etc.
I'm sorry for all the breakage this causes, but I think "System" is a
better name for this class (it makes it natural to add things like
"System.gc()") and frees up "IO" for referring to the CLI's IO module.
- Create separate libs for each architecture. OS X doesn't need this
(we just build a universal binary), but it will help Linux.
- Move the libuv build stuff into wren.mk where the actual dependency
on the lib is.
- Download libuv to deps/ instead of build/. That way "make clean"
doesn't blow it away.
- Don't redownload libuv unless needed.
* Eliminate "new" reserved word.
* Allow "this" before a method definition to define a constructor.
* Only create a default constructor for classes that don't define one.
Previously, fibers had a hard-coded limit to how big their stack size
is. This limit exists in two forms: the number of distinct call frames
(basically the maximum call depth), and the number of unique stack
slots.
This fixes the first half of this by dynamically allocating the call
frame array and growing it as needed. This makes new fibers smallers
since they can start with a very small array. Checking and growing as
needed doesn't noticeably regress the perf on the other benchmarks, and
it makes a new fiber benchmark about 45% faster.
The stack array is still hardcoded, but that will be in another commit.
