- added a function which tries to find the executable belonging
  to a core file if the extracted path does not exist
   - tries to find binaries with a relative path
   - tires to remove commandline arguments, since the core
     file does not store which part is the exe name (which can
     contain spaces), and which are arguments

loading /QT/core which was created by "/QT/bin/exec w.." by calling
  "./bin/exec with spaces" arg1 arg2 now finds the binary

==== will be split into a separate commit, included to show the
     second use of the new function

LoadCoreDialog: change when ExecFilename is set from core

- only set the name if the exe exists
- if it does not exist and the previous entry does not either
  then insert what was extracted from the corefile

Change-Id: I4a9846761c91ed976f3ba38a7dc756fc30ed179c
Reviewed-by: hjk <hjk121@nokiamail.com>