ucontext: updated to also restore VFP and CPSR registers
makefile changes to support tainttrap (adding anemu and preparation for file and thread hooks)
disabled VFP in libc (not supported by emu)
force enable arm compilation over thumb (make emu's life easier as arm support is better and easier to debug)
modified pthread internals to store sigaltstacks for emu handlers
added hooks for thread create/exit/free
disabled some taint logging in stdio as it's now part of emu itself
added optional memcpy optimization (currently disabled)
fixed TLS traps by aligning on 4K boundary