The code previously assumed that only functions can be closed over.

Previously, a realloc to a smaller memory chunk size would not free the
unused blocks in the tail of the chunk.

Remove zlibd, superceded by uzlib

Module "uzlib" - based on similarly named library

https://github.com/pfalcon/uzlib

os, time, select modules are now prefixed with u, but are still
available (via weak links) as their original names.

ure and ujson now available as re and json via weak links.

With this patch a port can enable module weak link support and provide
a dict of qstr->module mapping.  This mapping is looked up only if an
import fails to find the requested module in the filesystem.

This allows to have the builtin module named, eg, usocket, and provide
a weak link of "socket" to the same module, but this weak link can be
overridden if a file by the name "socket.py" is found in the import
path.

Viper can now do: ptr8(buf)[0], which loads a byte from a buffer using
machine instructions.

This is achieved by including re1.5 *.c files straight from modure.c .

Changes include:

regexp.h: Add double-include protection.

README: Update "unix" section with more info/details.

Add support for complimentary channel output and deadtime.

https://github.com/pfalcon/re1.5

https://github.com/pfalcon/re1.5

This patch enables output on the complimentary channels (TIMx_CHyN).
For timers 1 and 8, deadtime can also be inserted when the channels
transition. For the pyboard, TIM8_CH1/CH1N and TIM8_CH2/CH2N can
take advantage of this.

unix: Rename "microsocket" module to "usocket".

Per new conventions, we'd like to consistently use "u*" naming conventions
for modules which don't offer complete CPython compatibility, while offer
subset or similar API.