add demo ion sets to core library about ljpcalc

[swharden]

Done in https://github.com/swharden/LJPcalc/blob/master/src/LJPmath/KnownIonSets.cs

Example:

LJPcalc/src/LJPmath/KnownIonSets.cs

Lines 30 to 54 in f1d4ab8

	ionSets.Add(new KnownIonSet(
	name: "Ng and Barry (1994)",
	details: "Table 2 of: https://doi.org/10.1016/0165-0270(94)00087-W",
	expectedLjp_mV: -8.2,
	expectedAccuracy_mV: .5,
	ions: new List<Ion>(){
	new Ion("Ca", 50, 0),
	new Ion("Cl", 200, 100),
	new Ion("Mg", 50, 0),
	new Ion("Li", 0, 100)
	},
	ionTable: ionTable));
	ionSets.Add(new KnownIonSet(
	name: "JPCalcWin manual page 7",
	details: "JPCalcWin manual (page 7): https://medicalsciences.med.unsw.edu.au/sites/default/files/soms/page/ElectroPhysSW/JPCalcWin-Demo%20Manual.pdf",
	expectedLjp_mV: +8.74,
	expectedAccuracy_mV: 0.5,
	ions: new List<Ion>(){
	new Ion("Na", 10, 145),
	new Ion("Cl", 10, 145),
	new Ion("Cs", 135, 0),
	new Ion("F", 135, 0)
	},
	ionTable: ionTable));