Update readme to note output file option to cl.exe.

This is useful because windows gets really cranky about spaces and/or
parens in pathnames with msvc, so sometimes you have to run it from the
ECL folder, so you need to provide an explicit output location.
Add missing bracket.
Assume 32-bit architecture unless otherwise specified.

Older versions of ABL don't report their architecture with a preprocessor
flag. Since (according to Steve) we don't have any customers running a
64-bit client, assuming 32-bit architecture is safe for now.
Avoid using an undefined preprocessor name.
Fix typoed preprocessor names.
Define the cl_object type macro globally.
Separate type macros for FFI definitions and ABL code.
Rename include to indicate that it's raw ffi definitions.
Add include for generating variable-parameter versions of Call().
Use include to generate default single-arg Call() function.
Use less confusing #define name.
Supply export ordinal so we can use a unique procedure name.
Add wrapper functions for multiple-value macros.
Add function to convert lisp->c string.
Add FFI definitions for multiple-value functions.
Add FFI definition for lisp->c string conversion.
Add FFI definition for ecl_process_env().
Add procedure to check for and throw errors.
Add fixme note for later.
Add initial user-level API code.