fix for CASE expression in query with offset in ms sql
test added
add missing import for nested set

add import for the NestedSetRecursiveIterator
Added case-insensitive check for the version column
Added test for version column case insensitivity
Merge pull request #738 from iainmckay/versionable-caseinsensitive-column

Added case-insensitive check for the version column
Merge pull request #712 from loicbourg/fix-nestedset

add missing import for nested set
Merge pull request #711 from lars-fomin/mssql

fix for CASE expression in query with offset in ms sql