Partial refactoring and migration to TTreeReader
A step in the refactoring (shears#40 (closed)):
- Move the functionality for the EW corrections, b tag and pileup weights to dedicated classes.
- Add a class to provide access to command line options. It uses Boost.Program_options, thus introducing a dependency on Boost. Adjust the format of existing options.
- Switch to
TTreeReader
to read input ROOT files. Drop unused branches.