Fix bug opening schedule-file.
Merge with GUI.
Merge branch 'gui' of https://github.com/Alllex/Schedule
Merge with GUI.
Merge with develop-branch.
BugFix: check fields on null.
Add new construtor in the class Conflict.
Add conflict of blank fields in cards.
Remade conflict of blank fields in card using LINQ.
Returned groups in class sClassesTable.
Merge pull request #5 from Lozov-Petr/model

BugFix: check fields on null.