Create checks for discrete data files

[Klankers]

CTDCAL currently has very limited flagging on non-SBE data and often if there are questions/problems with the "raw" discrete data they go unreported until the data analysts have completed a run.

Adding these checks to CTDCAL when the files are initially assessed can help warn the data analyst in advance that they should find the temp/salinity/oxygen/nutrient analyst before they are off watch.

• [x] Temperature - frequency checks, formatting, looking for multiple runs
• [x] Salinity - questionable headers (standard dial irregularities), unorthodox standardizations, non-incrementing sample bottles, "outlier" conductivities (suggestive of standardization setting being too low), non-real answers, missing standardizations
• [x] Oxygen - ABORT lines, multiple headers, multiple standards, non-real answers, missing flasks in flasks.vol

[Klankers]

Removing the following bullet, as it's something that would be introduced in #67

• [ ] Nutrients (this is new)

[Klankers]

Completed reft checks. Not opting to automatically make new files if btl_fire_num resets, as SSSCC or station/cast information is not recorded in the .CAP files. Rather, warn the analyst.

[Klankers]

Salinity and oxygen checks implemented as of 906ea7c.

Ignoring flask number checks, as the merge step will just break if a flask is missing and that line is pretty obvious.