Recovering from broken .git tree. This includes the following commits:

 * 3a40290 app_blink is now buildable with PT.
 * 4ed74c7 Removed lifetime arg from lpc17xx::GPIO.
 * 0f60ef3 Temporary extracted pinconf to deal with lifetimes.
 * 831adb6 Generated args struct now uses correct lifetimes for refs.
 * d92eb08 Added os/single_task/args builder (a bit broken).
 * 070482f Using DUMMY_SP where possible.
 * 594a145 Parser now returns gc-wrapped platformtree.
 * 0a8cbd4 Fixed GPIOConf typo in generated gpio node.
 * 1d2f851 Tests are now always being built with `-g`.
 * e013567 Extracted TokenString to builder.
 * 51fa0c7 Added platformtee_verbose! macro to dump generated code.
 * 1a8cdb4 Cleaned up app_empty demo code.
 * 35de740 Very basic gpio subnode implementation for lpc17xx.
 * 6c75500 Basic timer subnode implementation for lpc17xx.
 * 3197ce6 Refactored test helpers to use pprust for source rendering.
 * 4267646 Starting refactoring work on app_blink.
 * 2b40597 Cleaned up app_empty demo, this one is done.
 * 7fe9f17 Debug build breaks IDA and Hopper, huh.
 * ef9a9af build_os builds a correct call to loop function now.
 * e64807b Compilation fixes for recent rustc version.