Fix memory leak in unix/main.c
Basic nspire support
nsp module

-Texture class
-waitKeypress function
-sys.exit exits cleanly
-3MiB heap
Add nsp.readRTC() function and turn on LTO and -Ofast
Get rid of unnecessary __del__
Add greyscale support (needs modified nspire-io)
Add nsp.Texture.setData function
Add base64 decoding for nsp.Texture.setData
Add msgbox if heap alloc failed
Fix build

-REG_RET not available in asmarm.c
-SSIZE_MAX not set
Add demo
Add "quit" shortcut for interactive mode
Maybe fix some crashes
Change texture.c comment