Added some functions towards new package

Added working script, basic time series plot, and two basic read_raw
type functions
Added example MAVEN output csv
made read_MAVEN drop NA rows

For some reason every other line in the read_MAVEN files is blank. Now
this function drops those lines *after* melting. Maybe it would be best
to drop the lines *PRIOR* to melting because there could be NA ion
counts for valid reasons.
added calc_12C (nonfunctioning)

Wrote beginning of (currently nonfunctioning) `calc_12()` function to
pick out the 12C ion for each sample
Apparently working calc_12C function

…but it has a ton of commented checking code