coincontroldialog: adapt the weight adjectives to typical weights

We have more blocks per second that bitcoin, and larger amount of
coins per output, so pretty much all blocks end up with "highest"
in short order. Move the goalposts by 100 so more of the range of
adjectives get used, so they become actually purpoesful.
Merge pull request #20 from moneromooo/weight-text

coincontroldialog: adapt the weight adjectives to typical weights