update to pxt 5 and pxt-common-packages 6 (#934)

* bump pxt

* fix build issues

* Auto-gen of projects/summary

* removing feild editors moved to pxt

* various typing fixes

* more typing fixes

* fixing various typing issues

* Start on integration of new pxt

* serial number fixes

* gc-ify MMap object

* Re-build generated files

* fix console listeners

* clear lf() warnings

* More generated files

* also auto-generated

* Compilation fixes

* fix merge

* mostly fixing blocks

* fix sim

* fix field motors

* enable a few features

* moving to tsx

* try to fix edtiro compilation

* more defs

* removing commands

* removing extra $

* fix blockly warning

* hiding images

* enabling more pxt features

* hide images

* setup autorun

* add lock on target_reset

* update deps

* return trylock result

* updated pxt

* rename video section

* add alpha channel

* upgraded pxt

* bump pxt/version

* removed alpha ref

* var ceanup

* don't do major bump

libs/core/shims.d.ts

@@ -68,6 +68,12 @@ declare namespace control {
     /** Write data to DMESG debugging buffer. */
     //% shim=control::dmesg
     function dmesg(s: string): void;
+
+    /**
+     * Determines if the USB has been enumerated.
+     */
+    //% shim=control::isUSBInitialized
+    function isUSBInitialized(): boolean;
 }
 declare namespace serial {