atoi()
Tweak build for user programs

Use standard C entry point for all user programs (int main(...)).
objcopy is used to rename the entry point after compilation, so that
other programs can refer to it.

Define protocol for user program sub-makes.  This makes it possible to
build user programs which have multiple source files.  The makefile in
usr/multi/ can be reused by changing the value of the $(objects)
variable.
Pass program name in argv[0]
Strip symbols from usr/ submakes
Merge branch 'master' of https://github.com/drewt/Telos

Conflicts:
	include/usr/test.h
	usr/eventtest.c
	usr/makefile
	usr/memtest.c