Fix compile with non standard types (#745)

* refactor tree utils

* fix compile + tree code refactor

* Add an extra test

* add a few missing activations to docs

* hash structure

* Encode the full argument structure

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Co-authored-by: Angelos Katharopoulos <a_katharopoulos@apple.com>

python/src/CMakeLists.txt

@@ -14,6 +14,7 @@ pybind11_add_module(
   ${CMAKE_CURRENT_SOURCE_DIR}/random.cpp
   ${CMAKE_CURRENT_SOURCE_DIR}/linalg.cpp
   ${CMAKE_CURRENT_SOURCE_DIR}/constants.cpp
+  ${CMAKE_CURRENT_SOURCE_DIR}/trees.cpp
   ${CMAKE_CURRENT_SOURCE_DIR}/utils.cpp
 )