Replace troublesome arithmetic operators
Use `isinstance()` for all type comparisons
Merge pull request #611 from stevensons/isinstance-for-comparisons

Use `isinstance()` for all type comparisons
Merge pull request #610 from stevensons/cut-safe-additions

Replace troublesome arithmetic operators
set x and y divisions in draw
add logy and logx options to plotting.utils.draw
FitResult: rename methods/properties to avoid conflicts with base class