Add support for -import delimited-

[matthew-white]

odkmeta uses insheet to import the ODK .csv data. Yet there are known bugs with insheet (e.g., involving embedded double quotes) that Stata 13's import delimited fixes. For users of Stata 12-, we should continue to allow the use of insheet, but for those who do have Stata 13, we should add support for import delimited.

[boyercb]

I think this may be a priority for IPA. We are slowly switching to Stata 14 which has dropped support for insheet.

[boyercb]

In which case, I'd argue for the following: odkmeta defaults to using import delimited and has an option to use insheet, as opposed to the reverse.