Multi-day accumulated fixes: tag dispatch, session/pooling correctness, SPA rollout, jetc compiler

JetCore engine (Tag.cpp/.h, Global.cpp/.h, __*.cpp tag classes):
- Numerous __mysql.cpp connection-pooling correctness fixes (stale
  result sets, double-indirection sessionid bugs, field caching,
  pool keying) and a session-registration-before-connection-confirmed
  ordering fix (dangling pointer on a failed connect)
- Tag.cpp: large body of fixes to the tag-dispatch/container-scanning
  logic (bare-name fallback, database aliasing, single-quote handling,
  @-prefix session variable resolution, TAGDEF caching, nested split-tag
  scanning for if/while/until/ifrow so an inner one doesn't corrupt an
  outer one's own boundary scan) plus the process-first rendering
  order fix (a <process> now runs before <checksession>/page
  resolution, fixing a real "blank page after successful login" bug)
- Global.h/.cpp: added imapSessions (parallel to the existing __mysql*
  session map) for the new <imap> tag family
- __whiledir.cpp/__include.cpp: caching and directory-name-aliasing
  fixes
- __call.cpp/.h: fixed a dangling-pointer bug
- __write.cpp: fixed an O_WRONLY-only open that couldn't create a new
  file
- __ifrow.cpp/__sql.cpp: fixed the same sessionid double-indirection
  bug __mysql.cpp had (resolveKeyword's result was being used as a map
  key lookup instead of the resolved value itself)

jetc compiler (jetc/JetParser.cpp/.h, JetCodegen.cpp/.h, JetAST.h,
jetc.cpp, build-shared.sh, build-compiled.sh):
- Parser fixes: inline <include>, nested-quote handling, void-tag
  recognition
- Codegen fixes and expanded AST support
- build-shared.sh: atomic rename into place for a freshly-built .jtc
  (a live server dlopen()ing the same path mid-rebuild was corrupting
  its own already-mapped view of the old file) and a staleness check
  so a cached JetCore .o doesn't silently keep serving yesterday's
  fixes forever
- Added -lssl to both build scripts' link lines (needed once the new
  <imap> tag's client-side TLS code existed - previously nothing in
  this codebase used OpenSSL's SSL/TLS client API, only libcrypto)

Site content (jetc/barant-site/): SPA (fetch-and-swap navigation)
rollout across essentially every .page/.jet/.section/.tag/.proc/.method
file - dynamic-content fixes, fragment-mode stripping, native
$[@name] session variables replacing older mechanisms, and this
session's own checkout.page redesign, login start-param redirect fix,
and per-page side-menu (menu.bar/$[PAGE].menu) refresh support.
Completed the earlier main.css/control.css move from assets/ to
assets/images/ (git still showed the old paths as tracked-but-deleted
until now).

Deliberately left out of this commit: dozens of .pre-<description>-
<date> manual backup files (this session's and earlier ones' own
before/after snapshots, not meant for permanent history), compiled
.jtc build outputs, ad hoc test binaries and scripts under jetc/
(login_asan, wcwc_test, optest2_bin, etc.), and jetc/__pycache__/ -
none of these are meant to be tracked; a .gitignore covering them
would be worth adding separately.

__call.cpp

@@ -16,14 +16,22 @@ namespace jet {
 	throw coreutils::Exception("call tag cannot have both input keyword and have a container.");	
       if(!keywordDefined("pgm"))
 	throw coreutils::Exception("pgm keyword must be specified.");
-      for(ix = 0; ix <= 50; ++ix)
+      for(ix = 0; ix < 50; ++ix)
 	argv[ix] = NULL;
-      argv[0] = resolveKeyword("pgm").c_str(); // TODO: Need to peel off the program name only and pass as argv[0].
-      for(ix = 1; ix <= 50; ++ix) {    
+      // Reserve up front - argStrings must never reallocate once a
+      // c_str() pointer from one of its elements has been stored into
+      // argv[] below, or that pointer dangles exactly like the bug this
+      // replaces (see the .h's own comment). 50 arg slots + argv[0]'s
+      // own program name.
+      argStrings.reserve(51);
+      argStrings.push_back(resolveKeyword("pgm")); // TODO: Need to peel off the program name only and pass as argv[0].
+      argv[0] = argStrings.back().c_str();
+      for(ix = 1; ix < 50; ++ix) {
 	 coreutils::MString arg("arg");
 	 arg << ix;
-	 if(keywordDefined(arg)) {	      
-	   argv[ix] = resolveKeyword(arg).c_str();
+	 if(keywordDefined(arg)) {
+	   argStrings.push_back(resolveKeyword(arg));
+	   argv[ix] = argStrings.back().c_str();
 	 } else
 	   break;
       }
@@ -54,7 +62,7 @@ namespace jet {
 	    close(fdi[1]);
 	    dup2(fdi[0], 0);
 	 }
-	 rc = execvpe(resolveKeyword("pgm").c_str(), argv, global.envp);
+	 rc = execvpe(argv[0], argv, global.envp);
 	 close(fdo[1]);
 	 exit(errno);
       }