Split Exec into smaller functions easier to manage

- introduce possiblity to book multiple cuts for the pion selections,
  each with its own histogram
- rho candidate lists are now members
New macros and tex files for group meeting pres. on 10/22

- Comparison macro to make sure that stylistic changes introduced in
  analysis code do not affect output files
- Efficiency numbers for pion identification
- Example macro for acessing mclist