Unit mismatch error is no longer as helpful

[grantfirl]

Upon finding a unit conversion mismatch, the exception: "Error, automatic unit conversion from X to Y not implemented" is raised without telling the user in which file and for which variable the mismatch occurs.

[grantfirl]

Suggest adding self.standard_name and self.container to exception message.

[climbfuji]

The user friendliness of this utility seems to be lacking ... do you want to address the issue? If not please assign it to me.

[grantfirl]

addressed in #216

[climbfuji]

Thanks @grantfirl