Add delay/reverb dry-wet, granular randomize toggles, rework accent DSP

- Add delay and reverb Dry/Wet parameters and knobs, wired into presets
- Add Accent/Slide/Fine/Rate toggles to the Randomize panel with new
  per-aspect pattern randomizers
- Soften accent: modest volume lift plus small cutoff and filter-attack
  modulation instead of the heavy 5x gain boost
- Halve reverb comb/allpass delays so the wet speaks sooner
- Regenerate a fresh build stamp on every build

cmake/WriteBuildStamp.cmake

@@ -0,0 +1,22 @@
+# Generates BuildStamp.h with the current date/time. Run as a build-time
+# custom command so the stamp is refreshed on every build (the TU that includes
+# it is recompiled because the header mtime changes each time).
+
+if(NOT DEFINED MONOSTEP_BUILD_STAMP_HEADER)
+    message(FATAL_ERROR "MONOSTEP_BUILD_STAMP_HEADER must be set")
+endif()
+
+string(TIMESTAMP STAMP "%Y-%m-%d__%H:%M:%S")
+
+get_filename_component(MONOSTEP_BUILD_STAMP_DIR "${MONOSTEP_BUILD_STAMP_HEADER}" DIRECTORY)
+file(MAKE_DIRECTORY "${MONOSTEP_BUILD_STAMP_DIR}")
+
+file(WRITE "${MONOSTEP_BUILD_STAMP_HEADER}"
+"// Generated at build time - do not edit.
+#ifndef MONOSTEP_BUILD_STAMP_H_INCLUDED
+#define MONOSTEP_BUILD_STAMP_H_INCLUDED
+
+#define MONOSTEP_BUILD_DATE \"${STAMP}\"
+
+#endif
+")