changelog
    
    
    - Sat, 26 May 2018 17:28:15 +0300
 
    - by Teemu Piippo <teemu@hecknology.net> [Sat, 26 May 2018 17:28:15 +0300] rev 1389
 
    - refactored signal blocking
 
    - Thu, 10 May 2018 15:54:26 +0300
 
    - by Teemu Piippo <teemu@hecknology.net> [Thu, 10 May 2018 15:54:26 +0300] rev 1388
 
    - fixed that scaling factors could be negative
 
    - Thu, 10 May 2018 15:48:39 +0300
 
    - by Teemu Piippo <teemu@hecknology.net> [Thu, 10 May 2018 15:48:39 +0300] rev 1387
 
    - added a doublespinbox variant that uses "." as the decimal point and omits trailing zeros