- moved source preparation from %build to %prep

- moved source preparation from %build to %prep
- simpliefed sed regex
- use macros instead fixed paths
- BR: sed >= 4.x for changing in place files
- use ___build_shell instead of /bin/bash
- mayby it's for linux only:
  $ a
  zsh: invalid system call (core dumped)  a
  on my FreeBSD box.
  $ truss a
  ioctl(134512773,0x1,0xbfbfea04)                  ERR#9 'Bad file descriptor'
  ioctl(134512773,0x1,0xbfbfea04)                  ERR#9 'Bad file descriptor'
  write(134512773,0x1,-1077941756)                 ERR#9 'Bad file descriptor'
  ioctl(134512778,0x1,0xbfbfea04)                  ERR#9 'Bad file descriptor'
  seteuid(0xbfbfea04)                              ERR#1 'Operation not permitted'
  obs_vtimes()                                     ERR#78 'Function not implemented'
  SIGNAL 12
  SIGNAL 12
  Process stopped because of:  16
  process exit, rval = 140
  zsh: invalid system call (core dumped)  truss a

Changed files:
    AsmEdit.spec -> 1.2