dtach-0.9+2.748020b-bp156.1.3

- use versionrewrite to properly set spec file version
- use https for downloading sources

- modernize specfile (move license to licensedir)

- Rewrite description to point out the objective features,
  and do so without relying to much on the user knowing GNU screen.

- Cleanup spec file with spec-cleaner
- Drop implicit build dependencies
- Fully utilise install command

- Remove __DATE__/__TIME__ macro use to allow reproducible builds

- Update to version v0.9+2.748020b:
  * Prevent buffer overflow with a long socket path name.
  * Try to use chdir to get around the sun_path length limit.
  * Add dtach -p.
  * Update copyrights for 2015.
  * Call init_pty before signals are set up.
  * Improve error message when dtach can't find a pty.
  * Update copyrights for 2016.
  * dtach 0.9
  * Update license address
  * Update license header in source files.
- Delete redundant dtach-remove-date-time-compile-macros.patch merged upstream

- New release based on version 0.9