Add a new RIP utility library

Currently, this has RIP.supported which returns true if RIP is
supported by the client, and rip.loadicons(archive) which sends
all the icons (and .RIP files) in the specified archive (either
an Arcive object or a filename) to the remote if they don't
already have them.

If you have a RIP enabled door, a small JS script as a pre-run
command like this:

require("rip.js", "RIP");
rip.loadicons('/sbbs/xtrl/lord/lordicns.zip');

Will automatically send all the icon files in the arcive to the
user if the user doesn't already have them.  For SyncTERM as of
this commit, they will be placed in the cache directory for that
BBS (and only be available for that BBS).

On *nix, the cache dir is ~/.syncterm/cache/<bbsname>
On Win32 it's something like:
C:\Users\User\AppData\Local\Microsoft\Windows\INetCache\SyncTERM\cache\<bbsname>

No ideal what it is on macOS.

exec/load/rip.js

+/*
+ * This will ensure that the remote system has the required
+ * RIP files if the remote terminal supports RIP.
+ */
+
+require("userdefs.js", "USER_RIP");
+
+var RIP = new function() {
+	var major = 0;
+	var minor = 0;
+	var vendor = 0;
+	var vsub = 0;
+	var queried_version = false;
+
+	function query(str, firstchar, resplen) {
+		var result = '';
+		var oldctrl = console.ctrlkey_passthru;
+
+		console.ctrlkey_passthru = -1;
+		console.write(str);
+		while (1) {
+			ch = console.inkey(0, 3000);
+			if (ch == '')
+				break;
+			if (result.length == 0 && firstchar !== undefined && ch != firstchar)
+				continue;
+			if (ch == '\n')
+				break;
+			result += ch;
+			if (result.length == resplen)
+				break;
+		}
+		console.ctrlkey_passthru= oldctrl;
+		return result;
+	}
+
+	Object.defineProperty(this, 'supported',  {
+		configurable: false,
+		enumerable: true,
+		get: function() {
+			var ch;
+			var result = '';
+			var oldctrl = console.ctrlkey_passthru;
+			var m;
+
+			if (major > 0)
+				return true;
+			if (console.autoterm & USER_RIP)
+				return true;
+			if (queried_version)
+				return false;
+			result = query('\x1b[!', 'R', 14);
+			queried_version = true;
+			m =result.match(/RIPSCRIP([0-9][0-9])([0-9][0-9])([0-9])([0-9])/);
+
+			if (m == null)
+				return false;
+			major = parseInt(m[1]);
+			minor = parseInt(m[2]);
+			vendor = parseInt(m[1]);
+			vsub = parseInt(m[1]);
+			if (major > 0)
+				return true;
+			return false;
+		}
+	});
+
+	this.loadicons = function(archive) {
+		var files;
+		var need = [];
+		var path;
+		var aborted = false;
+
+		if (!this.supported)
+			return false;
+		bbs.line_counter = 0;
+		print("Checking RIP icons...");
+		if (typeof archive != 'Archive') {
+			if (file_exists(archive))
+				archive = new Archive(archive);
+			else
+				return false;
+		}
+
+		files = archive.list();
+		files.forEach(function(fobj) {
+			var ext;
+			var result;
+			var m;
+
+			if (fobj.type != 'file')
+				return;
+			ext = file_getext(fobj.name).toLowerCase();
+			// TODO: Are any other types appropriate?
+			if (ext !== '.rip' && ext !== '.icn')
+				return;
+			bbs.line_counter = 0;
+			// TODO: Get/test date as well
+			result = query('!|1F020000'+fobj.name+'\r\n');
+			if (result.indexOf('0') == 0) {
+				print("Need: "+fobj.name+" (no such file)");
+				need.push(fobj.name);
+				return;
+			}
+			m = result.match(/1\.([0-9]+)/);
+			if (m === null) {
+				print("Need: "+fobj.name+" (bad response: '"+result+"')");
+				need.push(fobj.name);
+				return;
+			}
+			if (parseInt(m[1], 10) !== fobj.size) {
+				print("Need: "+fobj.name+" (size mismatch)");
+				need.push(fobj.name);
+				return;
+			}
+			print("Have: "+fobj.name);
+		});
+
+		if (need.length === 0)
+			return true;
+		need.unshift(false);
+		path = system.temp_dir;
+		path += 'ripicons' + bbs.node_num;
+		path = backslash(path);
+		mkpath(path);
+		need.unshift(path);
+		archive.extract.apply(archive, need);
+		need.shift();
+		need.shift();
+		need.forEach(function(fname) {
+			var type;
+			var ext;
+
+			if (aborted) {
+				file_remove(path + fname);
+				return;
+			}
+			ext = file_getext(fname).toLowerCase();
+			if (ext === '.rip')
+				type = '01';
+			if (ext === '.icn')
+				type = '02';
+			// TODO: Are any other types appropriate?
+			if (ext !== '.rip' && ext !== '.icn') {
+				file_remove(path + fname);
+				return;
+			}
+			bbs.line_counter = 0;
+			console.write('Sending: '+fname+'\r\n!|9\x1b06' + type + '0000<>\r\n');
+			// TODO: Somehow make sure 'G' is YModem-G?
+			if (!bbs.send_file(path + fname, 'G', 'RIP asset', false))
+				aborted = true;
+		});
+		rmdir(path);
+		return !aborted;
+	}
+}();