Basic single character dispatch.
Analyzer of command lines now works.
Fixes character rollback, counting lines, columns.
Remove old state handling.
Lexing of file lists, including remote names.
Added double quoted strings with expansions.
Read variables.
Fix bug when " is end marker of expandable.
Clean code for error reporting.
Error reporting.
Added export syntax.
Correct handling of comments.
Documentation.
Prepare for substitutions.