Change CacheRefreshTimer tick time back to 5 minutes
Some systems with whacky va_list implementations do undefined stuff when vsnprintf is called multiple times with the same list, so have InspIRCd::Format va_copy the list before each call
Add a va_copy define for Windows
Start to replace MAXBUF with <limits:maxline>.
Reserve ServerLimits::MaxLine instead of MAXBUF.
Compare to ServerLimits::MaxLine instead of MAXBUF.
Use iostream instead of C-style file operations.
Use InspIRCd::Format instead of snprintf().
Replace some C string operations with the + operator.
Rewrite irc::sockets::sockaddrs::str() completely.

- Replace use of MAXBUF with INET_ADDRSTRLEN/INET6_ADDRSTRLEN.
- Replace use of sprintf with InspIRCd::Format.
Convert ConvNumeric() to use std::string instead of char[MAXBUF].
Convert User::FormatNoticeMasks() to use std::string.
Convert User::SendText to use std::string.
Convert a ton of uses of MAXBUF to use a fixed buffer size.
Rewrite Channel::UserList to use std::string.
Remove hardcoded MAXBUF constant.