follow adapter naming for HSQLDBCompiler
less garbage from HSQLDB's visitor + note on #add_limit_offset!
Arel::SqlCompiler was only available with AR 3.0.0 pre-releases !
simplify some arel visitor code (using less garbage)
`add_limit_offset!` / `add_lock!` only to be overriden before AREL (AR 2.3)
make it explicit that `add_limit_offset!` modules are only needed on AR 2.3
make our SQLServer arel visitor extend the MSSQL built-in one if available
handle SELECT DISTINCT correctly with LIMIT (closes #154)
code inspired by @cmoran92's proposal
more AREL compatibility due (latest version in) AR 4.x
SQLServer visitor compatibility with AR 4.0 + simplify MSSQL's add_lock!
some more limit-offset related tests for MS-SQL (reproducing #410)
MS-SQL visitor update (based on built-in) to better resolve ORDER BY clause
+ make sure we work with next AREL (AR 4.1)