Changes from 2.6.1 to 2.6.2

• Updates to keep with API changes in newer NumPy versions (#228).
  Thanks to Oleksandr Pavlyk.
• Removed several warnings (#226 and #227). Thanks to Oleksander Pavlyk.
• Fix bugs in function stringcontains() (#230). Thanks to Alexander Shadchin.
• Detection of the POWER processor (#232). Thanks to Breno Leitao.
• Fix pow result casting (#235). Thanks to Fernando Seiti Furusato.
• Fix integers to negative integer powers (#240). Thanks to Antonio Valentino.
• Detect numpy exceptions in expression evaluation (#240). Thanks to Antonio Valentino.
• Better handling of RC versions (#243). Thanks to Antonio Valentino.