Scml

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* adding more details to tournament runs
* update to tournament utilities of SCML2020
* doc update and correcting a bug in world generation
* better initialization of production graph depth
* correcting default factory assignments (if any)
* making do_nothing agent really do nothing in scml2020
* removing unnecessary assertion
* correcting world generation using the new width first approach
* correcting world generation using the new width first approach
* documentation update
* adding no_logs option to SCMLWorld2019 and SCMLWorld2020
* changing default logging location for SCML2019 and SCML2020 to ~/negmas/logs/tournament
* changing the way worlds are generated in SCML2020 to minimize the number of agents per level allowing the depth to increase
* removing built docs from the repository
* modification to .gitignore
* updating .gitignore

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* adding components
* adding second tutorial

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* better tutorial
* better strategies

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* new interface for singing and callbacks
* new interface for exogenous contracts
* improved decentralizing strategy

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* correcting tournament implementation for SCML2020
* updates to SCML2019 agents to be compatible with newer versions of negmas

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* adding run2020 to scml commands (see the command line tool's documentation)
* Now tournaments run for SCML 2020 configuration