Hi and welcome to the forum.
You can use any IDE you want. Our team members use whatever seems comfortable: Eclipse, NetBeans, Komodo. You can use just a plain editor like Programmer's Notepad, Bluefish editor. It depends on what features you want to use - code autocomplete, collapsing sections of the code, integration with SVN or Git and other factors.
As for listing all callable objects - I know that our documentation is a weak point. The main source of documentation is our wiki http://www.epesi.org and we update it when possible. Please post you questions here on this forum and we will be glad to help you.