Remove unnecessary CACHEREAD for local file

The module relies on $ROOTSYS, uses bad CMake style with
include_directories() and link_directories() globally,
and doesn't work when used for a standalone build:

CMake Error at $ROOTSYS/cmake/modules/RootNewMacros.cmake:445 (install):
  install FILES given no DESTINATION!
Call Stack (most recent call first):
  $ROOTSYS/cmake/modules/RootNewMacros.cmake:964 (ROOT_GENERATE_DICTIONARY)
  CMakeLists.txt:105 (ROOT_STANDARD_LIBRARY_PACKAGE)

- Remove file globbing
- Inherit options from RInterface

TBB is not included as system anymore, so we need to avoid
warnings from its headers using a different method.

This causes problems both in depedency generation, since clang ignores
headers marked as system, and due to the order in which headers are
processed (build directory is marked as system when TBB is builtin).

Ensure that variables are actually read from the TTree...

ROOT-9620 #close

Sometimes the serialised methods will fail to load due to missing files.
This adds more output and checks to verify that required files exist to
better pinpoint the problem.

These headers are modular, this makes pcm a little bit smaller.

Use for evaluation same batch size as for training and not a fixed one of 1000

Use the template type (Scalar_t) instead of double, otherwise it will not compile for networks based on float types