Add Makefile for fpga directory (Windows codepath is untested, in any case, go.bat is still there)

Retire rbt2c.pl, instead use objcopy to directly convert the .bit file into an .o that can be linked with the flash image
Rename armsrc/fpga.c to armsrc/fpgaloader.c (since there is now a new fpga.o, created from fpga.bit)
Remove fpgaimg.c from subversion, add fpga.bit
Instead of creating fpgaimage.elf and osimage.elf separately, now create a joined fullimage.elf 
  first (obsoleting ldscript-full), then extract only the fpga and os sections with objcopy
  (This creates unspecific warnings about an empty segment, need to investigate)
Implement a rudimentary .bit parser in the firmware, use that to locate the bitstream in the new
  fpgaimage (which is just a plain copy of the fpga.bit file) and send it to the FPGA
  The code will check the format that's in flash and fall back to the legacy format

fpga/Makefile

@@ -0,0 +1,36 @@
+include ../common/Makefile.common
+
+all: fpga.ngc fpga.ngd fpga.ncd fpga-placed.ncd fpga.bit
+clean:
+	$(DELETE) fpga.bgn  fpga.drc  fpga.ncd           fpga.ngd            fpga_par.xrpt    fpga-placed.pad      fpga-placed.par       fpga-placed.xpi   fpga_usage.xml  xlnx_auto_0.ise  xst.srp
+	$(DELETE) fpga.bit  fpga.map  fpga.ngc           fpga_ngdbuild.xrpt  fpga.pcf         fpga-placed_pad.csv  fpga-placed.ptwx      fpga.rbt          xlnx_auto_0_xdb
+	$(DELETE) fpga.bld  fpga.mrp  fpga.ngc_xst.xrpt  fpga.ngm            fpga-placed.ncd  fpga-placed_pad.txt  fpga-placed.unroutes  fpga_summary.xml  netlist.lst     xst
+
+fpga.ngc: fpga.v fpga.ucf xst.scr util.v lo_simulate.v lo_read.v lo_passthru.v hi_simulate.v hi_read_tx.v hi_read_rx_xcorr.v hi_iso14443a.v
+	$(DELETE) fpga.ngc
+	$(XILINX_TOOLS_PREFIX)xst -ifn xst.scr
+
+fpga.ngd: fpga.ngc
+	$(DELETE) fpga.ngd
+	$(XILINX_TOOLS_PREFIX)ngdbuild -aul -p xc2s30-6vq100 -nt timestamp -uc fpga.ucf fpga.ngc fpga.ngd
+
+fpga.ncd: fpga.ngd
+	$(DELETE) fpga.ncd
+	$(XILINX_TOOLS_PREFIX)map -p xc2s30-6vq100 fpga.ngd
+
+fpga-placed.ncd: fpga.ncd
+	$(DELETE) fpga-placed.ncd
+	$(XILINX_TOOLS_PREFIX)par fpga.ncd fpga-placed.ncd
+
+fpga.bit: fpga-placed.ncd
+	$(DELETE) fpga.bit fpga.drc fpga.rbt
+	$(XILINX_TOOLS_PREFIX)bitgen fpga-placed.ncd fpga.bit
+
+
+.PHONY: all clean help
+help:
+	@echo Multi-OS Makefile, you are running on $(DETECTED_OS)
+	@echo Possible targets:
+	@echo +	all   - Make fpga.bti, the FPGA bitstream 
+	@echo +	clean - Clean intermediate files
+