Bug 6875 de-nesting C4::Heading

Bug 6875 de-nesting C4::Heading

C4::Search is needed only in authorities sub, moving it here and switching to
require

Signed-off-by: Jared Camins-Esakov <jcamins@cpbibliography.com>
Corrected call to SimpleSearch in both subs where it is used. Additional
performance improvements are included in bug 7284. 28 Jan 2012
(cherry picked from commit 58c46b27af601a893e1eabdfb5bd7d4d0d887f24)

Signed-off-by: Chris Nighswonger <chris.nighswonger@gmail.com>
(cherry picked from commit 0e61cfb3a591aec28521f2fdd1a76fea904721ca)

Signed-off-by: Chris Nighswonger <chris.nighswonger@gmail.com>