JSON parser should handle negative number

The JSON parse() method failed to parse the negative value -1.
Fixed issue and added unit tests around the case
JSON parser should handle negative number 2

Updated unit tests according to Sebatiean Ros demand
Merge pull request #85 from fredericaltorres/master

JSON parser should handle negative number
Ignoring VS14 ide files
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Merge remote-tracking branch 'upstream/master'