Revert "Bump up to version 2.0.0."

This reverts commit e30749f2d07e7844ab06c10ae5c7de3009557950.
Revert "Move iOS and OS X folders in a new folder named "Sample Client"."

This reverts commit 7f35b1cc8e29153322d6bc84495f04efc5888e9b.
Revert "Upgrade to new Xcode recommended settings."

This reverts commit e02a4dadd08e043d884f611af6fd6356df5553fe.
Revert "Making logic for creating cryptographic hashes more generic, and add SHA1 and SHA512 APIs."

This reverts commit 7b39d891fced492d74635c68fd31b2e5202baeed.
Revert "Rename folder "Common" as "Library"."

This reverts commit dd774cce3d0bc6b9394c643a38d8211c516730db.
Revert "Update copyright."

This reverts commit 9468991b8e811c05624d12df153599ac4005021f.
Revert "Rename Mac folder and target as "OS X"."

This reverts commit c07d253a497235621e6e8a5447159ea73d970386.
Revert "Modernize sample applications."

This reverts commit 52ae0651fb01744c7755b40bf7047e2f6cfff767.
Revert "New API for FileMD5Hash."

This reverts commit a6c9a4a8b438c30986758686ae6b24e2ec37911e.