add common files

.editorconfig

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+; This file is for unifying the coding style for different editors and IDEs.
+; More information at http://editorconfig.org
+
+root = true
+
+[*]
+charset = utf-8
+indent_size = 4
+indent_style = space
+end_of_line = lf
+insert_final_newline = true
+trim_trailing_whitespace = true
+
+[*.md]
+trim_trailing_whitespace = false

.gitattributes

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+# Path-based git attributes
+# https://www.kernel.org/pub/software/scm/git/docs/gitattributes.html
+
+# Ignore all test and documentation with "export-ignore".
+/.gitattributes     export-ignore
+/.gitignore         export-ignore
+/.travis.yml        export-ignore
+/phpunit.xml.dist   export-ignore
+/.scrutinizer.yml   export-ignore
+/tests              export-ignore

.scrutinizer.yml

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+filter:
+    excluded_paths: [tests/*]
+
+checks:
+    php:
+        remove_extra_empty_lines: true
+        remove_php_closing_tag: true
+        remove_trailing_whitespace: true
+        fix_use_statements:
+            remove_unused: true
+            preserve_multiple: false
+            preserve_blanklines: true
+            order_alphabetically: true
+        fix_php_opening_tag: true
+        fix_linefeed: true
+        fix_line_ending: true
+        fix_identation_4spaces: true
+        fix_doc_comments: true
+
+tools:
+    external_code_coverage: true

.styleci.yml

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+preset: laravel
+
+linting: true

.travis.yml

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+language: php
+
+php:
+  - 5.6
+  - 7.0
+  - 7.1
+
+env:
+  matrix:
+    - COMPOSER_FLAGS="--prefer-lowest"
+    - COMPOSER_FLAGS=""
+
+before_script:
+  - travis_retry composer self-update
+  - travis_retry composer update ${COMPOSER_FLAGS} --no-interaction --prefer-source
+
+script:
+  - phpunit --coverage-text --coverage-clover=coverage.clover
+
+after_script:
+  - wget https://scrutinizer-ci.com/ocular.phar
+  - php ocular.phar code-coverage:upload --format=php-clover coverage.clover