improve the description of gevent.
Merge pull request #460 from hnlq715/master

improve the description of gevent.
Add basic explanation of "Command-line Applications".

Basic explanation includes references to wikipedia and
application examples.
Format ``easy_install`` correctly
Monospace formatting for showing a command
Merge pull request #462 from mandarg/master

Minor doc fixes
Merge pull request #461 from Locker537/command-line-description

Add basic explanation of "Command-line Applications".
Eric IDE included and other ides improved.
Merge pull request #464 from rmoyano/idesection

I included Eric IDE and added more information to some IDE's descriptions.