Add support for HTTP/1.1 and random non-responsive devices #197

[bdraco]

Homekit needs the headers and content sent
in a single write call or it will randomly
get connection reset by peer which leads
to iOS stalling and devices showing up
as non-responsive.

Additionally we avoid connection resets
by draining any incoming data from the buffer
when we close the connection.

Without HTTP/1.1 keep-alives, 50+ devices
would cause a bridge to timeout or devices
to go non-responsive because homekit would
have to make a new connection to get / put
for each device. With HTTP/1.1 it can avoid
all of this overhead

After this change, devices in homekit on
the bridges with > 80 devices were
now immediately responsive in testing.

[codecov-io]

Codecov Report

Merging #214 into dev will decrease coverage by 0.66%.
The diff coverage is 37.5%.

@@            Coverage Diff             @@
##              dev     #214      +/-   ##
==========================================
- Coverage   60.97%   60.31%   -0.67%     
==========================================
  Files          16       16              
  Lines        1694     1706      +12     
  Branches      175      176       +1     
==========================================
- Hits         1033     1029       -4     
- Misses        622      638      +16     
  Partials       39       39

Impacted Files	Coverage Δ
pyhap/hap_server.py	32.79% <37.5%> (-1.65%)	⬇️

[bdraco]

I think I can simplify this a bit more. Will resubmit later

[bdraco]

Replaced with #216