make-thread no longer needs to reset the dynamic continuation
Setting new thread's dynamic wind state to a fresh root.
Patch from Lorenzo to fix previous incomplete patch.
Adding backslash line read tests.
\<space><newline><space> should only skip one line
Fixing source info tracking in \<newline> string escapes and multi-lined comments.
Conditionally define Complex and Ratio types.
Reset the current parameters in child threads.

This is simple and fast.  Inheriting all threads causes immediate
problems with exception handlers, and in general should use
copy-on-write behavior so that child threads can't affect parents.  If
we make an eager copy of the parameters we can filter out just the
exception handler, but then thread creation is expensive.  The ideal
design might allow selectively enabling parameter inheritance.
Disabling some simplifications that interact badly with GC.
Based on error report from Alan Watson.  Revisit this later.
Renaming dynamic-wind point routines to avoid likely user names.
Commented out warning.
Adding sexp_maybe_wrap_error utility to pass exceptions from the FFI without raising.
Fixes issue #156.
Better error message for mistaken usage of chibi-doc.
Fixes issue #177.
Binding C types, and adding declare-c-struct/class/union to access them from imported libraries.
Exporting sockaddr and addrinfo.