number extractors break on multiple decimal numbers

[ChanceNCounter]

extract_number() and extract_numbers(), at least in English, go completely haywire when there's more than one decimal number in the input string.

>>> lingua_franca.parse.extract_numbers("two point seven five and three point six")
[2.0, 7.0, 5.0, 3.0, 6.0]
>>> lingua_franca.parse.extract_number("two point seven five and three point six")
2

This may have a common solution with #88 and #92