Summary:
The numerical ordinal matching rule in DE is too broad. An ordinal like "1." may not be proceeded or followed by numbers.
* Added negative lookbehind - avoids matching the first "1." in "1.1" as an ordinal.
* Added negative lookahead - avoids matching the second "1." in "1.1. as an ordinal
Closes https://github.com/facebookincubator/duckling/pull/18
Reviewed By: patapizza
Differential Revision: D5069200
Pulled By: niteria
fbshipit-source-id: 0583076
b00e5faeac