* Support for multiple domains within --domain-filter
The parameter accepts a comma separated list of domains with or without trailing dot. Example: --domain-filter="example.org, company.test.,staging.com". Closes#247 and #229
* Add boilerplate header
* Add documentation for methods and structs
* use StringsVar for the domain-filter flag
* go fmt
* Remove camel case from tests
* Revert changes in README.md
* Move DomainFilter to provider package
* Make a new slice and copy elements to it
* Update CHANGELOG.md
* docs: change minor spelling mistake
* ref(source): use testify with mocks in test code
* fix: re-introduce NewMockSource for convenience
* fix: avoid circular dependency
* ref: increase usage of testify
* chore: vendor testify as a dependency
* fix(*): cleanup testify expectations
* feat(config): change defaults, switch flag processing to kingpin
* chore: vendor kingpin as a dependency
* feat(config): auto-detect cluster config from the environment
* chore: clean up definition of flags
* chore: sanitize flags even further
* chore: update changelog with latest flags changes
* fix(aws): fix messed up test name
* feat(aws): support multiple hosted zones and automatic lookup
* chore: run gofmt with the simplified command
* fix(aws): add missing method from google provider
* fix: remove superflous parameter from google provider
* feat: make domain configurable via flag
* fix(aws): remove unused constant
* fix(aws): don't log actions that were filtered out
* feat(aws): detect best possible zone to put dns entries in
* fix(aws): log error instead of failing if a change batch fails
* chore: update changelog with support for multiple zones
* feat(aws): support for creating DNS records with ALIAS type
* fix(aws): increase code coverage by listing ALIAS records
* chore: update changelog with support for ALIAS records
* ref(aws): generalize naming of ELB to load balancer
* ref(google): remove superflous check for non-existing record
* fix(aws): return the correctly typed alias record
* kickoff txt registry
* fix inmemory dns provider to include recordtype info for validation
* Merge master
* fix ununsed variable in inmemory provider
* add tests for records
* add test for no prefix name formatter
* implement apply changes with tests
* add flag to enable txt registry
* add txt registry to main
* improve sort testing
* filter out non-owned records
* NewEndpoint(...) requires record type
* use newendpoint in aws_test, fix tests
* change suitable type implementation
* fix the test for compatibility component
* change inmemory provider to include recordtype and use suitable type
* fix comments, CNAME should target hostname
* name mapper do not use pointer on struct
* txt prefix - just concatenate, remove spew, fix txt record label
* allow TXT records as result from dns provider
* add changelog
* fix tests
* TXT records need to be enclosed in double quotes
* feat(aws): support hostnames as endpoint targets
* docs: describe how to run ExternalDNS on AWS
* docs: update changelog with CNAME feature
* docs: update changelog to include AWS documentation
* fix(aws): test that updating records removes the old value
* feat(google): add CNAME support to Google provider
* fix(source): sanitize source and target hostnames
* docs: update changelog to include latest changes
* docs(aws): mention that ExternalDNS takes full ownership of a hosted zone
* fix(aws): switch route53 tests to use endpoint pointers
* docs: add TODO to remove record filtering once ownership is in place
