- Only have a single copy of all of the tasks_*.cpp sample implementations,
stored in examples/.
- Reduce dynamic storage allocation and locking in task launch code paths.
- Don't have a hard limit of the number of tasks that can be launched on
Windows (fix issue #85).
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.