Bumping minor version to 5.1
Bumping minor version to 5.1

Microsoft/pxt,switchinnovations/pxt,switch-education/pxt,switch-education/pxt,switchinnovations/pxt,switch-education/pxt,Microsoft/pxt,switchinnovations/pxt,switchinnovations/pxt,Microsoft/pxt,Microsoft/pxt,switch-education/pxt,Microsoft/pxt,switch-education/pxt