SCM_LENGTH -> SCM_STRING_LENGTH etc?

[Keisuke Nishida]

Hello,

It seems the macro SCM_CHARS has been renamed to SCM_STRING_CHARS
and SCM_SYMBOL_CHARS.  What about SCM_LENGTH?  I think it should
be renamed to SCM_STRING_LENGTH, SCM_SYMBOL_LENGTH, and SCM_VECTOR_
LENGTH, too.

Also, I'd like to see SCM_VELTS renamed to some better name, like
SCM_VECTOR_ELEMENTS.  Or instead, providing new macros SCM_VECTOR_REF
and SCM_VECTOR_SET might be better.

I think there was a plan to rename macros and functions in more
readable and consistent way.  When will it happen?  May I help?

And how about moving deprecated stuff to a single file all together?
It makes the header files cleaner.

-- Kei