add strict mode for parse_float() and parse_number()

[gamato]

What if Qore::parse_float() and Qore::parse_number() would accept 3rd arg "bool strict = False" that would turn on strict parsing that might a) return NOTHING or b) throw an exception (both in cases when input looked e.g. "1x2") ?

Atm they both silently drop non-numeric part of the input, which is surely not wanted in some / many cases.