v1.3.0

• new parameter "acceptable_range": allows to switch between van Westendorp's original definition of acceptable price ranges and a narrower definition which is used by some market research companies
• new parameters "pi_calibrated_toocheap" and "pi_calibrated_tooexpensive" for functions psm_analysis() and psm_analysis_weighted(): allows to specify a calibrated purchase probability at the "too cheap" and "too expensive" price, respectively, which is different from zero
• consistency: renames "trial" to "reach"