Minor Makefile corrections
Move SDK tool source code to a SDK source code folder
exp2lib: several Perl stylistic changes
Build system: many changes, see details:

- CONF_OUTDIR added in order to change the output directory
- stdlib structure changed to add crt0 pulling
feos/types.h: add attribute macros
fxe.ld: fix ctor/dtor table size detection
Kernel stdio: fix NULL pointer checks
Kernel console driver: add newlines to error messages
QEMU port: fix b0rked IRQ/timer code
QEMU: add WIP framebuffer driver
kmain.c: fix typo
Travis: add QEMU port to testing matrix