quiet noise if reporting error converting EACC

Since EACC strings can contain the % sign, this
patch removes the MARC8 string from the sprintf used by warning
message displayed if the codepoint cannot be found, getting
rid of the following spurious spew to STDERR:

  Missing argument in sprintf at ...

Signed-off-by: Galen Charlton <gmc@esilibrary.com>
add table for converting CCCII characters

At least one Japanese Z39.50 server in the wild that advertises
supplying MARC8 returns records that include the CCCII representation of
the halfwidth katakana middle dot character, which appears to
have no EACC equivalent.  This patch adds a new conversion table
for such characters as they get discovered.

Credit to Zac Craven for reporting the issue.

Signed-off-by: Galen Charlton <gmc@esilibrary.com>