EXPPP: output schema should match input schema

This is related to #244; awaiting feedback from Tom to verify that this fixes the problem.

* don't replace 'DIV' with '/' (01f6e26)
* aggregate initializers with repeat now work (263fcf1b9e, a75668e31, 7cad4abf6c)
  * however, repeat is incorrectly set at times - is the type_body shared?
* EXPRESS sci notation requires a decimal point (e8dfe9b, 5bf0a58)
  * also warn about and set locale
* break long strings (139d3f1, 80bf698)

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Minor changes:
* remove exptoks.h
* fix some warnings
* rename index_spec and limit_spec to bound_spec in expparse.y, to match the part 11 BNF
* replace all LISTadd with LISTadd_last, eliminate the LISTadd macro
* eliminate as many gcc warnings as possible in exppp.c and exppp-main.c
* remove code that created `rmpp` shell script
* insert spaces inside `()` and after `,` in pretty-printed EXPRESS
* libexpress line numbers were always off by 1