Add Algorithmic Environment documentation

[alfred100p]

I have added the documentation for algorithmic environments present on OpenAI gym.

Please note Reversed_Addition and Reversed_Addition3 have a single file and can be varied by giving rows parameter values 2,3 respectively.

The following work is still pending:

*Create a new table format to accommodate hyperlinks for value ranges that use parameters defined in the class
*Add documentation for Manual Control section
*Compute Average Reward

[alfred100p]

I corrected the previously wrong import statements in the tables.

[alfred100p]

The following work is still pending for Toy Text Environments:
*Add Version History for Taxi
*Create a new table format to accommodate hyperlinks for value ranges that use parameters defined in the class
*Add documentation for Manual Control section
*Compute Average Reward

[jkterry1]

Please put the two additions in separate PRs

[alfred100p]

I fixed the table structure. The following work is pending:
*Add Version History for Taxi
*Compute Average Reward for algorithmic and toy text environments

I'll make them into two PRs

[alfred100p]

Reopened as two separate pull requests:

• Add Algorithmic Environment Documentation(Add Algorithmic Env Documentation #2352 )
• Add Toy Text Environments(Add Toy Text Environment Documentation #2353)