don't crash on missing BWLimit section
Merge pull request #48 from lluis/issue_47

don't crash on missing BWLimit section
Removed the check against libocsync's versions.

It was confusing and didn't add anything.
Updated the csync_error_codes_e to the values of 0.90.4
Updated the csync_notify_type_e to the values of 0.90.4.
Updated the csync_ftw_type_e to the values of 0.90.4.
Updated the version numbers in the error 'handler'.
Applied slightly modified version of lluis' Pull Request.

Closes PR#47.
Use same sequence in usage section as in the documentation section.
Removed the line specifying the tested versions of libocsync.