Add coverage to Daubechies wavelet and scaling functions.

[NAThompson]

Closes #1264

[NAThompson]

Build failure is:

Cloning into '/drone/boost-root/tools/build'...
fatal: could not read Username for 'https://github.com': terminal prompts disabled
fatal: the remote end hung up unexpectedly
fatal: clone of 'https://github.com/boostorg/build.git' into submodule path '/drone/boost-root/tools/build' failed
Failed to clone 'tools/build'. Retry scheduled
Cloning into '/drone/boost-root/tools/build'...
fatal: could not read Username for 'https://github.com': terminal prompts disabled
fatal: the remote end hung up unexpectedly
fatal: clone of 'https://github.com/boostorg/build.git' into submodule path '/drone/boost-root/tools/build' failed
Failed to clone 'tools/build' a second time, aborting

Merging.