fixed an issue regarding defining global variables in C header files:…

… we should have defined rds_rough_col_type_t as a type rather than a global variable. thanks @姜大炮.

Catch-up with recent changes.

Add option to send original response body with error responses set by…

… "postgres_rewrite" directive.

Catch-up with recent changes (releng for 0.6).

Releng for version 0.5.