Renaming _describe() to describe()
Merge pull request #144 from wpreul/master

Renaming _describe() to describe()
Merge pull request #139 from iamdoron/master

empty string is not a number
fix a typo in README.md
Adding positive/negative options for number
Merge pull request #145 from iamdoron/patch-1

fix a typo in README.md
More tests
Merge pull request #147 from wpreul/master

Adding positive/negative options for number