allow ^D (EOF) to exit repl (instead of going into an infinite loop)
report error instead of crashing when magpie can't find "core" module in repl
Add type guard.
Merge branch 'master' of https://github.com/joshuawarner32/magpie
Clean up a bit.
Add skip() on Iterables.

Also get rid of generate(). It's a neat idea, but doesn't have the
right semantics since fibers are eager. Something like generate()
could be created, but it will need a pair of channels to ensure the
generator doesn't run ahead of the thing pulling from it.
Sketch in some float arithmetic tests.
Display uncaught errors to user.

Kind of hacked in, but the basic structure is there. This is a bit
tricky because toString needs to be called on the error object, so
we have to run some Magpie code after an unhandled error has
occurred.

Still need to make the various Error classes define useful toString
methods now.
Define each() on Iterable.
Make each, map, and where stop if the fn returns done.
Make "done" a reserved word and built-in type.
Simplify prime sieve example.
Rethrow if no catch clause matches.
Tweak how tokens are consumed after an error.
Get TCP connection listener sort of working.
Move TCP stuff into new "net" module.
Move native definitions into their respective files.
Reorganize natives and object code.
Clean up includes.

Not adding every subdirectory to the include paths now.
Also moved a few files around.
Start sketching in streams.

You can now kind of read data from a TCP connection. Sort of.