only compile .ts files in typescript service. fix for microsoft/pxt-microbit#86
only compile .ts files in typescript service. fix for microsoft/pxt-microbit#86

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