Bitmanip: Removed Comparator Flag to ALU

Created by: kevindkim723

Summary of changes:

• ZBB now uses LT, LTU signals generated within ALU to produce results for max(u)/min(u) B-instructions instead of comparator flags. This change increases verilog modularity.
• Renamed various signals in bit manipulation modules to match book.
• Improved verilog code style in various bit manipulation modules (spaces, redundant signals, etc).

Changes pass regression.