Switch from using 'nacl_main' to 'main' entry point

ports/fuseiso/README.nacl

 Original fuseiso is a standalone app, however for naclport,
 we chagned it to a library so that we can use it in other app.
 
 Major Changes for port fuseiso:
 1. added 'nacl_fuseiso_lib_init' and removed 'main' function in fuseiso.c.
  
 2. disabled the check for mnttab(fuseiso.c).
 
 3. disabled isofs_real_statfs, the parameters we have in nacl_io is statvfs,
    but in fuseiso, it requires statfs, also since we nacl_io currently 
    doesn't support statfs(more details see nacl_io/fuse.h in nacl_sdk).
 
 4. in currenl newlib, we don't have "bswap_16", using "__byte_swap_16" 
    from sys/endian.h instead.
 
 5. created a seperate Makefile.in for fuseisolib.
 
 Some sample code to test this lib(newlib version):
 
 //fusefoo.c
 
 #include <fuseiso_lib.h>
 #include <stdio.h>
-#include <fcntl.h>  
-#include <unistd.h> 
+#include <fcntl.h>
+#include <unistd.h>
 
-int nacl_main(int argc, char* argv[]) {
-
+int main(int argc, char* argv[]) {
   char* path = "<YOUR ISO PATH>";
   char* mount_point = "/foo";
   char* fs_name = "fuseiso_fs";
   mkdir(mount_point, 0777);
   nacl_fuseiso_lib_init(path, mount_point, fs_name);
 
   char buffer[1024];
   int fd = open("/foo/<PATH_IN_ISO>", O_RDONLY);
 
   read(fd, &buffer,1024);
@@ skipping 15 matching lines @@
 
 $NACLSDKPATH/toolchain/linux_x86_newlib/bin/x86_64-nacl-gcc \
   -I$NACLSDKPATH/include -L$NACLSDKPATH/lib/newlib_x86_64/Release \
   -L$NACLSDKPATH/toolchain/linux_x86_newlib/x86_64-nacl/usr/lib \
   -L$NACLSDKPATH/toolchain/linux_x86_glibc/x86_64-nacl/usr/lib \
   -o fusefoo_newlib.nexe fusefoo.o  -Wl,--undefined=PSUserMainGet \
   -Xlinker -uPSUserMainGet -lcli_main -lnacl_spawn -lppapi_simple \
   -lnacl_io -lppapi -lfuseiso -lstdc++ -lncurses -lglib-2.0 -lz -lintl
 
 Should be able to get a fusefoo_newlib.nexe after complie and link.
-Copy fusefoo_newlib.nexe and the iso file to devenv to test it.
+Copy fusefoo_newlib.nexe and the iso file to devenv to test it.