Rakefile: identifier, versions, code signing

- Pre-Alpha version
- Avoid com.yourcompany domain
- Don’t code sign
- app.archs['MacOSX'] = ['x86_64']
  workaround as for http://hipbyte.myjetbrains.com/youtrack/issue/RM-240
  to avoid "ld: warning: PIE disabled. Absolute addressing (perhaps
-mdynamic-no-pic)
  not allowed in code signed PIE, ..."