Disable valgrind for the FFTW builds
Add an address-sanitizer build mode
Fix bug in ppgen found by address sanitizer
Try enabling a memory sanitizer build as well
Remove the memory sanitizer config, was triggering inside of libstdc++
Merge pull request #118 from mwiebe/asan

Tweaks to the travis.yml to speed things up, try to use clang's asan, etc
Fix fftw compile error
Create design doc arrfuncs.md
Add files for arrfunc registry support
get_regfunction and set_regfunction functions
Add init/cleanup functions for the arrfunc registry
Put some basic functions in the registry
Switch the few registered functions to use multidispatch, add tests