kohabug 2475 [3/?] Adding splitting algorithm for fiction call numbers

kohabug 2475 [3/?] Adding splitting algorithm for fiction call numbers

This patch also looks for the call number type in items.cn_source and if
that is NULL, falls back to the DefaultClassificationSource syspref.

Splitting algorithms need to be written for other known/supported call
number systems (ie. sudocs, udc, generic, etc.)

Documentation Notes:

For now, if a call number falls through the regex checking for formal lccn or ddcn,
it is passed through the regex for a fiction call number; if it falls through that,
it is returned unsplit.

If a call number does not split, please update enhancement request 2500 with the
requested information.

http://bugs.koha.org/cgi-bin/bugzilla/show_bug.cgi?id=2500

Signed-off-by: Joshua Ferraro <jmf@liblime.com>