More interesting initial and boundary conditions for reaction diffusion 2
Incorporate name of parent func in name of "parallel for" task function.

This gives us easier to decypher function names, a la
"par for FooBar.s0.y.yo", rather than just "par for s0.y.yo",
which made it hard to analyze profiling data from programs
with multiple Halide functions.
Add box filtering and clean up
Merge pull request #227 from mmp/master

Incorporate name of parent func in name of "parallel for" task function.
Added missing header guard
Miscellaneous code cleanups.

Including removal of old implicit args.
Performance fix for chain of filters using store_root().compute_at(output, y)
Added parallelization and vectorization; Cleanup.
Merge branch 'master' into resize_example
Bugfix for is_monotonic of a select
Bugfix for nested sliding windows.
Changed cascaded filter test to be simpler and to check the value.
Merge remote-tracking branch 'origin/master' into resize_example
Add different schedules and redefine '-s' option to switch between them.
Move resize app to its own directory
Fixed error checking for missing implicit args

I removed the code that adds implicit args even when _ is missing, but didn't
add a check to make sure the number of args was correct. This resulted in
allowing through bad function calls.
Better header hygiene
Added a test for usage of the old implicit args syntax
Added some missing docs.
Fixed sliding window behavior to work for resize.