v0.5.0

• Fixed bug with incorrect behaviour in TIDE algorithm: if candidate point was idx_base, it was skipped.
• Changed logic for point selection and brackets.
  Now for positive trend we use the candidate point (idx_cand) and (a,b] brackets; for negative - idx_cand+1 and [a,b) brackets
• Changed text brackets for -inf, +inf borders to always be '(' or ')'
• Visual improvements for plots
• Added sample_rate in stats for convenience
• Rewrited some docs
• Added 'tide' mode for categorical bins handling