tree: move firmware targets under a new per-target container dir
tree: mv board-info.mk files under board-specific directories
tree: relocate board_hw_defs files into board-specific directories
tree: auto-discover targets in the flight directory
tree: move pios_board.h variants to board-specific directories
tree: move cmsis system_* board files to board-specific directories
tree: move hardware docs to board-specific directories
tree: move gdb config files to board-specific directories
tree: flatten fw source tree structure
makefile: pass paths to sub-makes explicitly
gdb: remove stray gdb config file
tree: relocate bootloaders to board-specific directories
tree: flatten bootloader updater
makefile: adapt ef targets to new make variables
tree: adapt sim builds to new make variables
tree: move UAVObjects and UAVTalk outside of targets subtree
tree: rename per-board firmware main file to main.c
Merge pull request #754 from solidgoldbomb/hw-grouping

Group board-specific files together