Add quality checks currently used by PASTA

[gothub]

Implement quality checks, initially as unit tests, that correspond to the checks that are currently part of the PASTA check suite. For testing, these will be implemented as python and R scripts.

Here is the current set:

dataset checks

• [x] packageIdPattern
• [ ] emlVersion
• [x] schemaValid
• [ ] parserValid
• [ ] schemaValidDereferenced
• [x] keywordPresent
• [x] methodsElementPresent
• [x] coveragePresent
• [x] geographicCoveragePresent
• [x] taxonomicCoveragePresent
• [x] temporalCoveragePresent
• [x] titleLength
• [x] pubDatePresent
• [x] datasetAbstractLength
• [ ] duplicateEntityName

  entity checks (metadata)

• [x] entityNameLength
• [x] entityDescriptionPresent
• [x] numHeaderLinesPresent
• [x] numFooterLinesPresent
• [x] fieldDelimiterValid
• [x] recordDelimiterPresent
• [x] attributeNamesUnique
• [x] databaseTableCreated

  entity checks (congruency)

• [ ] urlReturnsData
• [ ] onlineURLs
• [x] examineRecordDelimiter
• [x] tooFewFields
• [x] tooManyFields
• [x] dataLoadStatus
• [ ] numberOfRecords

  entity checks (data)

• [x] displayDownloadData
• [x] displayFirstInsertRow

[leinfelder]

It seems like this is becoming our default check suite (which is great). But means we have to flesh out every check by including a good name, description, and helpful output message[s] to assist users that encounter a failure.