`puts` should print "\n" only when the argument does not end with "\n".

Modify exception handling

If an exception is raised before cipush is called in mrb_run,
it should be handled in the outer mrb_run.

now segmented list can be used as instance variable tables by -DMRB_USE_IV_SEGLIST; we still need to measure the performance and memory consumption

Struct.new crashed if no parameters given. This pull request fixes that.

Minor edits to Xcode project file to better support Xcode 4.4 and OS X 10.8

Fixed memory leak when calling stack_extend in m->body.func

Fix message lengths.

mrb_run(): Fix not to use a magic number but sizeof.

Fix a memory leak in mrb_realloc().