Merge pull request #13 from dietsche/f3ed5b38f784f8035cd2b82367e3069a9745a0ca

Toggle line numbers correctly when switching windows
Configuration variable for {en,dis}abling the default toggle key

* Additional check for g:UseNumberToggleTrigger
* Extended documentation
Merge pull request #16 from jrk-/keytoggle

Configuration variable for {en,dis}abling the default toggle key
Merge remote-tracking branch 'upstream/master'