Breaking Changes
correctly compute duration for `erfsquare` waveform templates
Features
support underscores in `erfsquare`, `padleft`, and `padright`
check for `pad_left` and `pad_right` on all waveforms, include `_` in `erf_square`
expose iter on ExternSignatureMap
Fixes
fix computation of duration for `erfsquare` waveform templates
ensure extern signature map is publicly accessible
ensure extern signature map is publicly accessible (410)