polle 1.0

- Package documentation: https://arxiv.org/abs/2212.02335

polle 1.2

- action sets can now vary across stages (stage_action_sets)
- g_empir() is a new g-model useful for calculating the empirical (conditional)
probabilities
- conditional() estimates the group specific policy value estimates
- progressr is now implemented for policy_eval()
- sim_single_stage(), sim_two_stage(), and sim_multi_stage() are new functions
for simulating data.