* Fix bug in hierarchical searches using sheet path pointers which are
destroyed on every search. Use human readable path as last sheet found
in test to prevent comparison of deleted pointers.
* Fix a bug in SCH_COMPONENT::Matches() that would prevent searching for
pins if the search all fields flags was not set.
* Fix a bug in SCH_COMPONENT::Matches() to use the sheet path to perform
the comparison to the correct reference designator and unit number.
* Fix wrapping in sheet path and sheet path list MatchNextItem methods.
* Push search methods down to EDA_ITEM object so advanced searching can
be performed on all items derived from EDA_ITEM.
* Add virtual method to EDA_ITEM object to test if item supports replacing
text.
* Replace switch statement magic numbers in Eeschema socket connection code
with Pcbnew for improved readability.