fixed bug 2394
Fix Bug number 2393
bug fix 2398
fixed bug 2395
code review for ritesh changes
Adding completed Dodos problem to the server; updating documentation.
Clean up of 'sessions.md' file.
Fixing typo in dodos problems.
Merge branch 'ritesh'
fixed check empty expression message
Merge branch 'master' into pradeep
Merge branch 'pradeep'
Merge branch 'master' into stable