Debinterface

Added
- ipv6 support
- 'source' directive support: wildcard sources files can now be loaded
- 'nameservers' directive support
- mypy typing (thanks ObjatieGroba)
- update dev dependencies

Fixed
- Fix interfaces unique names checking on dnsmasq (thanks ObjatieGroba)
- Changing exported dict should not affect on adapter (thanks ObjatieGroba)
- Fix module version specification (thanks ObjatieGroba)
- support for lines with spaces in param value (thanks ObjatieGroba)
- handle lines with spaces in the parameter section (they were dropped) (thanks ObjatieGroba)

Fixed
- Add missing post-up handling (thansk patrickcjh)
- Increased portability using short args (thanks lucascoelhof)

Added
- wpa-conf to adapter and reader/writer. (thanks mikeodr)

Fixed
- parsing of options dict as 'bridge-opts' as this is the true attribute
title when reading it back from 'attributes' accessor. (thanks mikeodr)
- existing parsing of set_options for dns-search. (thanks mikeodr)

Fixed
- Bug with new ability to add comments

Added
- Ability to provide header comments (thanks mikeodr)
- Parsing of 'dns-search' (thanks mikeodr)
- Adding missing option 'bridge_maxwait' to interfaces writer. (thanks mikeodr)

Fixed
- Only one DNS IP was being read or written by the library. (thanks Jude188)
- Strict ordering of dns-search option after the dns-namerservers (thanks mikeodr)

Added
- Docs to read the docs :-)
- Class can be imported more easily as in the example : from debinterface import Interfaces
- DeprecationWarning for hotplug key, will be changed to allow-hotplug in 4.0

Changed
- PR from mchubby: chmod destination file to 0644
- dnsmasqRange.rm_itf_range returns False is nothing was changed
- Removed validation code from NetworkAdapter to its own class
- Do not backup/restore if creating a new interfaces file

Fixed
- shutil.copy is replaced by os.rename which is atomic
- bad if/else
- failing tests
- NetworkAdapter : missing pre-down, post-up functions
- ifup command was not an absolute path (thanks ymolinet)