specIO improved import for Bruker files

Julien Tréboscrequested to merge
mrrc/nmrzoo/ssnake-test:jt_bruker_import_fixes into develop

This MR covers several issues:

  1. When looking for potential SF in different procno, searching for valid procxs is done walking through sub-directories. Import will fail if user has made in procno directory a sub-directory with procxs file inside (e.g. pdata/12/backup/proc2s). New search looks only for valid procno in pdata (directories whose name is only made of digits), containing procxs file without recursing into sub-sub directories.
  2. Many checks are done to see if file exists. But it is more accurate to check if file to open is a regular file. It also returns False if file does not exist.
  3. For XWINNMR 1.1 FnMODE does not exist, and import will fail (#333 (closed)).
  4. A test is added for a WINNMR 1.1 2D datasets import

These 4 points have been solved in 4 separate commits.

Merge request reports