log: use more clear defaults

Before log module creates everything in same directory and it gets messy
in some time.

Now log module creates directory in format $USER/$NETWORK/$WINDOW and
there log files for every day in ISO 8601 format, YYYY-MM-DD.log.
Merge pull request #667 from Mkaysi/log

log: use more clear defaults
Allow wildcards in help command args

Supports the help command for *status, all modules that are using
CModCommand as appropriate, and *controlpanel get/set variables.
Tell user about no help filter matches

It's confusing if misspelled command gives no reply at all.
Allow network specific quit messages (resolves #273)
controlpanel: add support for network specific quit messages (#273)
webadmin: add support for network specific quit messages (#273)
Merge pull request #670 from jpnurmi/quit-msg

Allow network specific quit messages
Merge pull request #669 from jpnurmi/help

Allow wildcards in help command args
Fix finding SWIG 3 on FreeBSD
Travis: use -fPIE

TSan sometimes fails to build without it.
https://travis-ci.org/znc/znc/builds/35293091