convert long numbers to strings in response

[jwillinghalpern]

adds a new convertLongNumbersToStrings option to Filemaker.create(). Setting this to true converts long numbers such as those produced by FileMaker's Get(uuidNumber) and Random functions into strings rather than returning scientific notation with reduced precision.

This is the issue which prompted this feature: Luidog/node-red-contrib-filemaker#61. I haven't checked if fixing fms-api-client alone addresses the issue fully because I haven't tried this change with node red.

This part of the changed code felt a bit repetitive, not of a better way offhand though:

fms-api-client/src/models/client.model.js

Line 393 in a1453bf

parseScriptResult(body, this.agent.convertLongNumbersToStrings)

[coveralls]

Coverage increased (+0.006%) to 99.446% when pulling 9fbb585 on feature-longnumbers into 753bbda on master.