Release v4.6.0

• Skipping over 4.5.x versions since George Phillips had used that
  point release line for his work.

• Git repo "cw2dmk" of Tim Mann's work was created by ezrec
  (Jason S. McMullan). Transferred to qbarnes.

• Switched Linux release binaries to be for 64-bit OSes.

• Added change from George Phillips for his "join" (-j) feature
  that will join different rereads of the same track and merge
  good sectors.

• Fixed problem of missing data between index hole detect and read
  started. This should noticably reduce disk read errors and even
  occasionally dropping of entire sectors.

• Added change to allow cw2dmk tools to function on newer Linux
  releases by enabling PCI I/O space access if disabled.

• Added change to recognize and skip factory-formatted sides of a
  disk. Controlled with -b option.

• The subdirectory "cwsdpmi" is now a git sub-module for picking up
  the "cwsdpmi.exe" binary for MS-DOS.

• Cleaned up and merged multiple makefiles for different environments
  into one. Makes it easier to maintain, build, and cross-build. By
  default, the Makefile will now only build for the native OS. See
  the new file BUILDING.md for further information.

• Created subdirectory "firmware" for holding firmware related files
  including a LICENSE file. I also received some additional
  documentation from Jens Schoenfeld on programming the MK3 and MK4
  and a file with firmware revision history saved here as
  firmware/Changelog.

• To be less generic, renamed "testhist" binary to "cwtsthst", still
  keeping to MS-DOS's 8.3 file naming convention.

• Update code base to be 64-bit clean. Fixed all known problems but
  some may remain.

• Changed to using semantic versioning for version ID.