doc(clear): clear moved from result to group
doc(clear): clear moved from result to group

Previously, calling .clear() on the validation result resets it to valid, nonDirty, however this is usually used in the context of 'clearing' out a form.  There was a timing issue where the Observers would notify the validation of the form properties 'resetting their value' after the validationResult.clear() had been executed, causing the validation to consider the cleared form as dirty.
This has been addressed, but the clear() had to move to validation-group instead of validation-result.

Fixes #44
manuel-guilbault/aurelia-validation,manuel-guilbault/aurelia-validation,hitesh97/validation,JeroenVinke/validation,santosh-suresh/validation,mbroadst/validation,bellstrand/validation,RichTeaTime/validation,bfil/validation,JeroenVinke/validation-fix,aurelia/validation,ericIMT/validation,PWKad/validation,atsu85/validation,jdanyow/validation,Bcpoole/validation,charlespockert/validation,Bcpoole/validation,DaveGee/validation,valichek/validation,vulvulune/validation,JeroenVinke/validation,milunka/validation,RichTeaTime/validation,DaveGee/validation,mbroadst/validation,vulvulune/validation,DavidBLynch/validation,aurelia/validation,ericIMT/validation,PWKad/validation,JeroenVinke/aurelia-validation-update,milunka/validation,Zensavona/validation