[Initial import of David Lester's ERA module.
lennart@augustsson.net**20060618124632] 
[Rename.
lennart@augustsson.net**20060618124729] 
[Update for Haskell 98.  Get rid of warnings.
lennart@augustsson.net**20060618124746] 
[Get rid of unnecessary fromInteger.
lennart@augustsson.net**20060618125216] 
[Drop trailing decimal zeroes.
lennart@augustsson.net**20060618125950] 
[Rename the implementation module.
lennart@augustsson.net**20060618130251] 
[Add the module that export CReal.
lennart@augustsson.net**20060618130321] 
[Get module names right.
lennart@augustsson.net**20060618130744] 
[Add test.
lennart@augustsson.net**20060618130814] 
[Add more Enum instances.
lennart@augustsson.net**20060618133424] 
[Add PHONY
lennart@augustsson.net**20060618133459] 
[Add erf function.
lennart@augustsson.net**20060618133523] 
[Just test erf once.
lennart@augustsson.net**20060618134512] 
[Make comment about this being wrong.
lennart@augustsson.net**20060619031247]