Extend support to Word2Number

[lfoppiano]

This PR attempts to extend the support of the word 2 number algorithm, so that we can cover also the forms such as 3.6 billion. We also include the incorrect words "billions, millions, etc.."

[coveralls]

Pull Request Test Coverage Report for Build 8463142128

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 101 unchanged lines in 2 files lost coverage.
• Overall coverage increased (+0.5%) to 34.462%

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Files with Coverage Reduction	New Missed Lines	%
org/grobid/core/utilities/WordsToNumber.java	27	81.91%
org/grobid/core/engines/ValueParser.java	74	1.36%

Totals
Change from base Build 8447466255:	0.5%
Covered Lines:	2332
Relevant Lines:	6365

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💛 - Coveralls