Change of the selling priority, following item quality instead of a r…

…andom pick (#104)

* Initialization fixed to be performed at script startup; included copyright in the new source files

* Handle of the configuration reloading in the correct way from the command line (cleanup and initialization of new elements)

* Improved the help text and descriptions

* Introduced a mechanism that allows the bot to adapt to the market prices (right now is a plain average which resets to allow quick convergence with the markets sentiments)

* Threshold for market per-item price reset now implemented as a configurable value

* Adjusted the license on the source files

* Change in item selection for the selling operations; instead of using a random pickup, which can always result in bad rolls and waste of cycles, the selling priority now follows the items rarity. First the bot will try to fill up poor items, and then when quotas are reached it will move to more rare ones