- factor out runWithEnv
- require explicit connect() call to avoid rechecking for oDB
(more for readability than for speed)
- clean DSNInfo of empty strings and simplify check for entries
Switch to functions server_version_num and postgis_lib_version
which both only return the version string, so that no elaborate
string parsing is necessary anymore. The version string could
become especially cumbersome in pre-release versions.
