Labels Cleanup (Part 1 of Many)

Labels Cleanup (Part 1 of Many)

Consolidated error catching after evals.
Removed unnecessary $sth->finish calls and some unused variables.
Pulled query for itemtype mappings outside DrawSpineText and added
a class level caching variable to eliminate repeated queries for
*each piece of text* on *each label*!  This was a major performance
downside.

Note: this does not fix Unicode problems, but it does add some notes
on unsuccessful attempted workaround using utf8::encode.

C4::Labels should likely be broken up to separate out the pieces that
do not touch the database (wrappers of PDF::Reuse) and those that are
CRUD API for table data.

Signed-off-by: Galen Charlton <galen.charlton@liblime.com>