Question of starting codition order TS72 vs. KMN15

[jrenaud90]

Kamata et al. (2015) has the two starting solutions for RadialSolver k^2 +/- (see their Eq. B13) implying that solution 1 uses the + version and solution 2 uses the minus.

Takeuchi & Saito (1972) have similar starting solution definitions but order them as -/+ (see their Eq. 99).

TidalPy has the option to use both starting solutions. For Kamata we use +/- and for Takeuchi we use -/+. See the respective equations in "RadialSolver.starting".

[jrenaud90]

• Check if this makes a difference to begin with (try flipping solution 1 and solution 2)
• If it does then try to determine which is correct
• Update code and TODOs for starting condition functions in "RadialSolver.starting"