Fix DirectoryExist for symlinks
Debug build. Some unit tests for DirectoryExist
Some code formatting
Allow to choose another shell or directory if console startup failed

  For example, if your saved named task was created for some directory,
  which was deleted at some moment. ConEmu will suggest to show standard
  'Create new console' dialog where user can change command and directory.
ConEmu will check directory existence before creating new tab

  If you type wrong startup directory for new process
  in the 'Create new console' dialog, ConEmu will check it,
  show warning and allows to change it to smth better.
Downloader fixes
ConEmuC&Downloader - wrong logging function used
All internet code (Updater) moved to ConEmuCD.dll