Fix warning in vector_math
Added comments on vectorization of transcendentals
Added a function to test if an expression is one-to-one. Will be useful for parallelizing reductions.
Fixed warning
More reliable timing for fast pow test
Even more consistent timings for fast pow test
Made timing more consistent in all tests by using clock instead of gettimeofday
Made it clearer that unsigned division method 0 is handled by power_of_two case
Made test_apps compile on os x with system c++
Fix find_inverse.c so that it generates a correct table.

For signed i32 division by 209, it was inaccurately accepting a multiply
by 1315205297 and a shift by 6 for that, even though the correct result
is 2630410593 and 7.   Now, it does 10x more random samples of values
and generates the right result.

(The checked in table is correct, though; presumably it was generated
with a different version of find_inverse.  Sending this patch in to
avoid trouble in the future.)
Merge branch 'master' of git://github.com/halide/Halide
Fall back to gettimeofday on systems with a small CLOCKS_PER_SECOND
Merge pull request #121 from mmp/master

Fix find_inverse.c so that it generates a correct table.
Reverted to gettimeofday due to portability problems
Merge branch 'master' of github.com:halide/Halide
merged