src/template/: Rename LineByLineParser to LineByLineLexer.
src/template/shorthand-php.php: Update comment for 'expandShorthandPhpLogic'.
src/template/: Delete LineByLineParser.php (should have been committed with commit that renamed LineByLineParser to LineByLineLexer).
src/array.php: Add alias/wrapper for 'at' function that's available in the top-level/default namespace (as defined in types.php).
src/template/shorthand-php.php: Rework 'expandVariablesInTextPart' so as to avoid considering irrelevant '-' and '>' characters bordering a variable name as part of the "shorthand variable syntax" if they aren't a complete "object operator" (i.e., '->').