Remove unused variables.
Comment out unused functions.

Commenting out is done using #if 0 ... #endif.
Declare tagtransform_shutdown in tagtransform.h.

It is used in output-pgsql.c.
Add necessary includes in tagtransform.c.
Avoid dangling else by adding braces.
Replace erroneous assignment with comparison.
Merge pull request #91 from RavuAlHemio/unwarn

fix some compiler warnings