Moved crc* and md5.* to src/hash

Removed v4upgrade from sbbs project.

crc* and md5.* was moved to src/hash
base64.* was moved to src/encode

You'll need to perform a clean rebuild.

You will need to perform a clean rebuild.

You will need to perform a clean rebuild.

You'll need to perform a clean build.

You'll need to perform a clean build.

translation.

MIME-encoded headers.

translation from CP437 -> UTF-8 and only when using high-level text output
functions - so the output from native/DOS doors and scripts that use low-level
output methods won't be translated.
UTF-8 is auto-detected (only) at this time during answer (before login) by
sending a ZWNBSP and checking (via ANSI) if the cursor position moved - an
idea "borrowed" from Ozz Nixon (aka SqZ).

This commit requires the new "encode" library (src/encode), so you may need
to perform a cvs checkout to get that module!

Prepare for upcoming "hash" library.

this insures:
1. the timestamp always includes the seconds
2. the tiemstamp is always in 24-hour format (no am/pm indication)

For systems that are configured (in SCFG) for "Military" (24 hour) time format,
the error.log timestamps should appear the same as before.

Use "save/restore" uifc.list() mode for "Save Changes" prompt - no need to
leave the prompt visible while saving changes.
Display pop status while saving changes to config file.

Copy/paste errors from 2002 (changes -> uifc.changes in the help text).
Use "save/restore" uifc.list() mode, rather than "remain active" for
"Save Changes" prompt - no need to leave the prompt visible while saving
changes.

When processing area manager netmail messages, SBBSecho can modify
(add/change) keys in the [node:*] section of the sbbsecho.ini file. Although
SBBSecho would read node sections that had a domain (e.g. 5D address) just fine
when processing area manager changes and writing those changes back to the
sbbsecho.ini, only 4D addresses (no "@domain") were used in the section naming.
This could result in duplicate node sections being created in the sbbsecho.ini
file (one with a "@domain", one without) and then "bad things" could happen
(e.g. BinkP authentication failures, packet authentication failures, etc.).

Now, when SBBSecho writes linked-node setting to the sbbsecho.ini, it first
checks for the full 5D address of the node and if that section exists, modify
it, otherwise fall-through to the 3D/4D address of the node for the sectoin
naming.

getting kind of crazy common now and being employed even when totally
unnecessary (e.g. encoding strings that contain just plain ASCII):
- normalize message header fields, when possible
- normalize UTF-8 encoded characters, when possible (e.g. special punctuation
  chars)

This allows text filters (e.g. subject.can, name.can) to work on MIME-encoded
header fields and notifications about received e-mails are legible to humans.

Encoded-words that contain actual non-ASCII/CP437 chars (e.g. foreign symbols,
emojis) are left as encoded-words to be dealt with by whatever displays the
message header.

Special handling of folded normalized field values was necessary because
"White space between adjacent 'encoded-word's is not displayed." (per RFC 2047)

line 34: Error: can't open \sbbs\exec\undefined.js: No such file or directory