Better diagnostics for multiple component/action registerations under the same name

[brycelelbach]

[reported by blelbach] [Trac time Thu Aug 18 01:53:15 2011] This error frequently crops up when we copy/paste examples and forget to change the unique names that are passed to the registration macros. We need to diagnose this better as this sort of error currently has cryptic symptoms.

[brycelelbach]

[comment by blelbach] [Trac time Tue Feb 28 22:01:46 2012] One facet of this problem: It is possible to create two component classes, give them the same component name, and load them at once. Both components get the same component id, and no explicit error is generated until the components are actually used.

[brycelelbach]

[comment by blelbach] [Trac time Tue Apr 17 19:30:09 2012] Work done for this in r7753

[brycelelbach]

[comment by blelbach] [Trac time Tue Jul 3 00:15:41 2012] Milestone 0.9.0-rc2 deleted

[hkaiser]

That's supposedly fixed. Please reopen, if needed.