xpressn.c, fix semantics of `int(x)' and remove dangerous macros

int(x) most probably shall be trunc(x) instead of floor(x)
  note trunc(x) was #defined beeing floor(x)
  note ln(x) was #defined beeing log(x)
xpressn.c, drop "Defd" enum, to be incorporated into a bigger enum
xpressn.c, use enums instead of literals
xpressn.c, drop XFU_V

probably accidentally introduced in commit

> Author: h_vogt <h_vogt>
> Date:   Sun Feb 7 11:27:59 2010 +0000
>
>     improved numparam error message
xpressn.c, implement a?b:c in the "formula" parser
xpressn.c, whitespace cleanup
inpcom.c, drop ternary_fcn code in inpcom.c, the extended "formula" shall process ternary expressions
inpcom.c, exclude currently unused functions
xpressn.c, drop '&' and '|' operators, (we have '&&' and '||')
xpressn.c, use C strings for the arguments of `keywords()'
xpressn.c, drop "AND OR NOT DIV MOD DEFINED" keywords
xpressn.c, drop initkeys()
numparam, almost full precision for stringified double float numbers
tests/regression/lib-processing, fix upper/lower case
tests/regression/parser

check xpressn.c parser capability to parse {2--3}
check .control parser capability to parse 2--3
check B parser capability to parse 2--3

check echo commands capability to print "--"
check echo commands capability to print upper and lower case

check xpressn.c parser capabilities

check precision of some transcendental functions
Man page fixes.

- Start new sentences on a new line, so that troff gets inter-sentence
  spacing correct.

- Remove unterminated quotation mark.

- Replace no-longer-defined "spice" macro with a literal string.

- Remove trailing whitespace.

- Close literal contexts instead of letting them propagate throughout an
  entire section.
Remove unnecessary include of sys/timeb.h.
MIFget_boolean(), allow numeric values 0 and 1 too
fix commit "numparam, almost full precision for stringified double float numbers"
replacements for functions missing in the msvc world