COMP: Fix warnings and missing include

This patch addresses the following warning:
itkBinShrinkImageFilter.hxx:117:54: warning: declaration of
'OffsetValueType' shadows a global declaration

by removing the unused type.

And addresses compilation errors related to:
itkBinShrinkImageFilter.hxx(157): error C2039: 'multiplies' : is not a
member of 'std'

by including the functional header.

Additionally the initial accumulate is cast to size_t to ensure
correct implicit template parameters to accumulate.

Change-Id: I69c5b78b96c2801ce3ffc85c271158464a1a7476
BUG: Fix Valrgrind detected delete mismatch

This patch addresses the following Valgrind detected defect:
 ==10520== Mismatched free() / delete / delete []

Change-Id: Id831307cfb31d8bb39315f97d6df4620916fc1d7
ENH: improve coverage for SetShrinkFactor methods

Change-Id: I51f41d3ae2da54c3cdafed75090f3580ec04730d
Merge topic 'BinShrinkCoverage'

3e3bce4 ENH: improve coverage for SetShrinkFactor methods
Merge topic 'BinShrinkFixValgrind'

67c8324 BUG: Fix Valrgrind detected delete mismatch
Merge topic 'BinShrinkFixComps'

b5f0fa1 COMP: Fix warnings and missing include