Internet Download Manager

What's new in this version:

New features:
- ifconfig-ipv6(-push): allow using hostnames (in place of IPv6 addresses)
- new option: --ciphersuites to select TLS 1.3 cipher suites (--cipher selects TLS 1.2 and earlier ciphers)
- enable dhcp on tap adapter using interactive service (previously this required a privileged netsh.exe call from OpenVPN)
- clarify and expand management interface documentation
- add Interactive Service developer documentation

User visible changes:
- add message explaining early TLS client hello failure (if TLS 1.0 only clients try to connect to TLS 1.3 capable servers)
- --show-tls will now display TLS 1.3 and TLS 1.2 ciphers in separate lists (if built with OpenSSL 1.1.1+)
- don't print OCC warnings about 'key-method', 'keydir' and 'tls-auth' (unnecessary warnings, and will cause spurious warnings with tls-crypt-v2)
- bump version of openvpn plugin argument structs to 5
- plugin: Export base64 encode and decode functions
- man: add security considerations to --compress section

Bug fixes:
- print port numbers (again) for incoming IPv4 connections received on a dual-stacked IPv6 socket. This got lost at some point during rewrite of the dual-stack code and proper printing of IPv4 addresses.
- fallback to password authentication when auth-token fails
- fix combination of --dev tap and --topology subnet across multiple platforms (BSDs, MacOS, and Solaris).
- fix Windows CryptoAPI usage for TLS 1.2 signatures
- fix option handling in combination with NCP negotiation and OCC (--opt-verify failure on reconnect if NCP modified options and server verified "original" vs. "modified" options)
- mbedtls: print warning if random personalisation fails
- fix subnet topology on NetBSD (2.4)