Eeschema find/replace bug fixes and improvements (fixes 1208616).

* Fix replace bug to handle case sensitivity properly.
* Fix replace bug where the item index was getting updated incorrectly.
* Fix replace infinite loop bug on replace all.
* Make find/replace view update code a separate function.
* Rearrange find/replace trace string to add tracing to EDA_ITEM::Replace().
* Add IsComplexHierarchy method to SCH_SHEET_LIST for future find/replace
  improvements.