Added ZIP_UTIL_PKG as library and included in install script.
files all lowercase
Delete APEXIR_XLSX_PKG.pks
Delete APEXIR_XLSX_PKG.pkb
Delete APEXIR_XLSX_TYPES_PKG.pks
Delete XLSX_BUILDER_PKG.pkb
Delete XLSX_BUILDER_PKG.pks
Delete ZIP_UTIL_PKG.pkb
Delete ZIP_UTIL_PKG.pks
Merge pull request #2 from commi235/refactor

Refactor