add number-of-impressions + simulator parameters are tuned

New feature

number of impressions

• The policy output now contains another column named num_impressions. It contains the number of impressions from which the clicks are generated.
• Actually, these values are approximates to keep simulator runtime low. Exact tracking for impression counts is a future task (needs rework in simulator loop structures).

time spent by simulator and policies

• A new output file, output_time_spent_in_seconds.xlsx , contains cumulative time spent for simulator and each policies.
  • Each row corresponds to each iteration.

Bugfixes

• Fixed unnecessary repeated line prints in some of policy output xlsx files, which may happen with last attribute tuple.
• Simulators run up to number of iterations defined by max_t parameter given in the init xlsx file. This max_t value is the same as the max_t provided to policies.

Simulator parameters tuned

• The auction generating parameters are modified to result in much more frequent auctions, clicks, and revenues to make statistical learning faster.
• The variance of revenue random variable is reduced to make statistical learning easier.
• The init file used for the first run is included (auction_ini_01.xlsx updated).