Multiple changes in schematic & projects:

-Added net classes for controlled impedance traces
    -Added power hierarchical sheet
    -Initial USB subsystem schematic
    -Added multiple bus definitions (usb, pcie, i2c etc.)
    -Fixed busses use
    -Added LDO for audio analog rails

Signed-off-by: Dominik Sliwa <dominik@sliwa.io>

Power.kicad_sch

@@ -0,0 +1,8 @@
+(kicad_sch (version 20201015) (generator eeschema)
+
+  (paper "A4")
+
+  (lib_symbols
+  )
+
+)