I had an easy install using the directions given dated 25 october 13 on
https://code.google.com/p/sigil/issues/detail?id=2279
Sigil-0.7.3-Mac-Package
I removed all sigil files to Trash, including the default dictionary.
I enabled xcode, and on the security preferences, I enabled allow apps downloaded from anywhere. The dmg file opened, and worked on all the epubs files I had been proofing.
Phew, so glad to have Sigil back!