Replace deprecated repo and update to latest
Merge pull request #4 from rintaun/patch-2

Replace deprecated repo for conformance tests
Added spyc as a git submodule.
Fixed merge
Updated twitter-text-conformance to latest.
Remove incorrect merge message in README
support cctld .sx
Change tests library

change YAML reader to symfony/yaml, and twitter-text-conformance will be
fetched using composer.
remove submodule
remove README
remove unuse const in phpunit.xml
Twitter_Extractor::extractRepliedUsernames() check end_mention_match
extractURLs check invalid short domain
extractURLs In the case of t.co URLs, don't allow additional path characters
extractURLs more correctly
rewrite Extractor::extractURLs(), Extractor::extractURLsWithIndices()
fixes Extractor::extractURLs
Extractor::extractHashtags, extractCashtags uses these Indices method
Extractor::extractMentionedUsernames uses these Indices method
rewrite Extractor::extractHashtagsWithIndices