Casio fx-CG series port (#324)

* Initial test - working on Linux

* Try to make it work with liba

* Stop using liba and the filesystem

* IT WORKS

* Key input, full res, fix some of the crashes

* Fix the hang when doing calculations

* Add some more key mappings

* Fix the square root issue

* Icons

* Better key mappings, brightness control, better gamma correction, more effficient framebuffer

* Cleanup stage 1

* Cleanup stage 2

* Make the build system build a g3a

* Make it not exit when you press the menu button

* Add Casio port to README

* Use omega-master instead of omega-dev

* Fix mistake with cherry-picking in the README

* Fix internal storage crash

* Fix compile error on Numworks calculators

* Upsilon branding

* Sharper icon

* Make the CI work

* Add power off and improve menu

* Map Alpha + up/down to the brightness shortcut

* Add missing file

* Fix web CI build

* Revert "Fix web CI build"

This reverts commit f19657d9fc.

* Change "prizm" to "fxcg"

* Add FASTLOAD option for Add-in Push

* Add some charatcers to the catalog on Casio and improve key mappings

* Build with -Os -flto

* Disable LTO for now as it's causing crashes

* Put back the fonts I accidently changed

I'd like to add an option for this though as I prefer the ones from Epsilon

build/platform.simulator.fxcg.mak

@@ -0,0 +1,11 @@
+TOOLCHAIN = sh-elf-gcc
+EXE = elf
+
+EPSILON_TELEMETRY ?= 0
+
+HANDY_TARGETS_EXTENSIONS = g3a bin
+
+USE_LIBA = 0
+POINCARE_TREE_LOG = 0
+
+SFLAGS := $(filter-out -fPIE, $(SFLAGS))

build/targets.simulator.fxcg.mak

@@ -0,0 +1,5 @@
+$(BUILD_DIR)/%.bin: $(BUILD_DIR)/%.elf
+	$(OBJCOPY) -O binary -R .bss -R .gint_bss $< $@
+
+$(BUILD_DIR)/%.g3a: $(BUILD_DIR)/%.bin ion/src/simulator/fxcg/assets/icon-uns.png ion/src/simulator/fxcg/assets/icon-sel.png
+	$(FXGXA) --g3a --icon-uns=ion/src/simulator/fxcg/assets/icon-uns.png --icon-sel=ion/src/simulator/fxcg/assets/icon-sel.png -n Upsilon $< -o $@

build/toolchain.sh-elf-gcc.mak

@@ -0,0 +1,10 @@
+CC = sh-elf-gcc
+CXX = sh-elf-g++
+LD = sh-elf-g++
+GDB = gdb
+OBJCOPY = sh-elf-objcopy
+SIZE = sh-elf-size
+AS = sh-elf-as
+FXGXA = fxgxa
+
+SFLAGS += -D_FXCG -D_BIG_ENDIAN