Makefile and vcxproj file updates.
Also modified vcxproj files so that the various files ispc generates go into $(TargetDir),
not the current directory.
Modified the ray tracer example to not have uniform short-vector types in its app-visible
datatypes (these are laid out differently on SSE vs AVX); there was an existing lurking
bug in the way this was done before.
Within each function that launches tasks, we now can easily track which
tasks that function launched, so that the sync at the end of the function
can just sync on the tasks launched by that function (not all tasks
launched by all functions.)
Implementing this led to a rework of the task system API that ispc generates
code to call; the example task systems in examples/tasksys.cpp have been
updated to conform to this API. (The updated API is also documented in
the ispc user's guide.)
As part of this, "launch[n]" syntax was added to launch a number of tasks
in a single launch statement, rather than requiring a loop over 'n' to
launch n tasks.
This commit thus fixes issue #84 (enhancement to launch multiple tasks from
a single launch statement) as well as issue #105 (recursive task launches
were broken).
Link the appropriate clang libraries to make the preprocessor
stuff work on Windows builds. Also updated the solution files
for the examples to stop using cl.exe for preprocessing but to
just call ispc directly. Finishes fixes for issue #32.
