HTTPS server, better Automaton.spawn

[gpotter2]

Various random fixes:

• fix memory leak when using Automaton.spawn
• add a HTTPS_Server variant of the HTTP_Server
• fix export_object and import_object
• fix bug in .show() in LatexTheme
• fix NTLM SSP when against libcurl
• drop base64_bytes from tests

[codecov]

Codecov Report

Attention: Patch coverage is 51.28205% with 19 lines in your changes missing coverage. Please review.

Project coverage is 81.58%. Comparing base (a5dab9e) to head (5f1129c).

Files with missing lines	Patch %	Lines
scapy/automaton.py	55.00%	9 Missing ⚠️
scapy/layers/http.py	27.27%	8 Missing ⚠️
scapy/layers/kerberos.py	0.00%	1 Missing ⚠️
scapy/layers/ntlm.py	66.66%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4520      +/-   ##
==========================================
- Coverage   81.59%   81.58%   -0.02%     
==========================================
  Files         356      356              
  Lines       85215    85248      +33     
==========================================
+ Hits        69528    69546      +18     
- Misses      15687    15702      +15     

Files with missing lines	Coverage Δ
scapy/themes.py	91.46% <ø> (ø)
scapy/utils.py	73.41% <100.00%> (-0.04%)	⬇️
scapy/layers/kerberos.py	67.43% <0.00%> (ø)
scapy/layers/ntlm.py	87.29% <66.66%> (-0.10%)	⬇️
scapy/layers/http.py	82.34% <27.27%> (-1.05%)	⬇️
scapy/automaton.py	75.00% <55.00%> (+0.04%)	⬆️

... and 7 files with indirect coverage changes