Add some genjava asserts, mostly for documentation.

Perhaps, however, the real fix is to allow the full char range, not just the
positive ones. I added these asserts to document an assumption already
present in the code. C code generation probably has these, as well.
make install for monitor now installs to $HOME

instead of copying to ra
turn some buffer macros into functions

also, add some asserts to buffer code
make struct buffer private to buffer.c

also, changed some whitespace in fint.c to match the surrounding code
adapt genjava to buffer.h changes
Merge branch 'assertions'