Add overview to README
prefer markdown for github
Remove -march=armv6 if -mcpu is already specified in compiler options --- it breaks older gcc
Fix Beagle builds

For the toolchain we have, armv6 is incompatible with cpu=arm1136jf-2, but
with cpu-cortex-a?, arch=armv7-a is required.
Fix compilation errors on Cortex-A8

Different version of GCC need diffferent combinations of -mcpu
-mtune= and -march to build properly for KZM (armv6) and cortex-a8

Make CFLAGS and ASFLAGS consistent, and rely on GCC knowing which arch is which
wwhen told what CPU to build for.
More compiler fixes

The in-kernel-directory Makefile was trying to reset CFLAGS, and
sometimes sets them to conflict with the ones set by the Kbuild system.

Only set CFLAGS and ASFLAGS for standalone builds.
(standalone builds are only really supported for KZM anyway).
merge
bump API version number
Add links to "seL4.systems" website to "README.md".
Do not discard user PYTHONPATH when building
Merge pull request #6 from adanis/pythonpath

Do not discard user PYTHONPATH when building
Merge branch 'master' into experimental

Conflicts:
	README