Add testproxy e2e tests for POP3 and SMTP protocol validation.
We have detected that POP3 and SMTP protocol validation was broken
thanks to these new testproxy e2e tests. This is yet another example why
e2e tests are important.
Because we directly relay the packets from the server to the client
until we receive the first packet from the client, at which time we xfer
srvdst to the first child conn and effectively disable this readcb,
hence start diverting packets to the listening program.
Improve documentation.
Create function macros for fine* debug logs
Fix a few memory leaks when DEBUG_PROXY enabled
Add main.mk to MKFS list
Put a few function params within DEBUG_PROXY directives
Check retval of a snprintf() call
Fix segfault with -w/-W options if no ssl proxyspec specified, also fixed in sslsplit develop: https://github.com/droe/sslsplit/issues/271
Various clean-up