>FLOAT with leading and trailing spaces

[gerryjackson]

FLOAT is tested in the provisional floating point test package src/fp/to-float-test.4th. This tests for compliance with the BNF specification for >FLOAT in section 12.6.1.0558 of the standard which does not allow for leading and trailing spaces in the input string. This is somewhat inconsistent given that a "string of blanks should be treated as a special case representing zero". This leads to at least one system failing a few tests. Options are:

1. Permit leading and trailing spaces but report that the system ignores them. This is in line with issue #2 'Reporting of Forth characteristics'
2. Leave alone

Given the provisional nature of the floating point tests and the fact that very few systems seem to have tried these tests, this will be left for now in the hope of further feedback.