TCTL Updates

[sabaronett]

Tasks

• [x] 46561620ce65fbaee18ebb8011e7cc5340d660c7 c6d536e8f557b5f5d29c51c91d685dd9f783f949 Fix tctl_tau value and update plots in ipython_examples/TidesConstantTimeLag.ipynb and examples/tides_constant_time_lag/problem.c.
• [x] 246b2d2a94af6262dc32833b0bbe787aab7314b1 c6d536e8f557b5f5d29c51c91d685dd9f783f949 Change all instances of k1 and tctl_k1 to k2 and tctl_k2 in src/* to match §3.1 of Baronett et al. (2021) and avoid confusion in Python example.
• [ ] Specify radius cutoff parameter to include tides between particles.

[dtamayo]

Closing this now, thanks @sabaronett !