Fixes travis config file

Fixes the mess due to #995 and #1005.

Fixes:
* Remove --standard - codesniffer.ruleset.xml was renamed to phpcs.xml which gets picked automatically by PHPCS.
* Install PHP Compatibility sniffs.
* Add PHP Compatibility to install path for PHPCS sniffs.

.travis.yml

@@ -29,6 +29,10 @@ env:
 # e.g. copy database configurations, environment variables, etc.
 # Failures in this section will result in build status 'errored'.
 before_script:
+    # Set up temporary paths.
+    - export PHPCS_DIR=/tmp/phpcs
+    - export WPCS_DIR=/tmp/wpcs
+    - export PHPCOMPAT_DIR=/tmp/phpcompatibility
     # Set up WordPress installation.
     - export WP_DEVELOP_DIR=/tmp/wordpress/
     - mkdir -p $WP_DEVELOP_DIR
@@ -49,14 +53,14 @@ before_script:
     # Create WordPress database.
     #- mysql -u root -e "CREATE DATABASE wordpress_test;"
     # Install CodeSniffer for WordPress Coding Standards checks.
-    - mkdir php-codesniffer && curl -L https://github.com/squizlabs/PHP_CodeSniffer/archive/3.5.0.tar.gz | tar xz --strip-components=1 -C php-codesniffer
+    - git clone -b master --depth 1 https://github.com/squizlabs/PHP_CodeSniffer.git $PHPCS_DIR
     # Install WordPress Coding Standards.
-    - mkdir wordpress-coding-standards && curl -L https://github.com/WordPress/WordPress-Coding-Standards/archive/2.1.1.tar.gz | tar xz --strip-components=1 -C wordpress-coding-standards
-    # Hop into CodeSniffer directory.
-    - cd php-codesniffer
-    # Set install path for WordPress Coding Standards
+    - git clone -b master --depth 1 https://github.com/WordPress-Coding-Standards/WordPress-Coding-Standards.git $WPCS_DIR
+    # Install PHP Compatibility sniffs.
+    - git clone -b master --depth 1 https://github.com/wimg/PHPCompatibility.git $PHPCOMPAT_DIR
+    # Set install path for PHPCS sniffs.
     # @link https://github.com/squizlabs/PHP_CodeSniffer/blob/4237c2fc98cc838730b76ee9cee316f99286a2a7/CodeSniffer.php#L1941
-    - bin/phpcs --config-set installed_paths ../wordpress-coding-standards
+    - $PHPCS_DIR/bin/phpcs --config-set installed_paths $WPCS_DIR,$PHPCOMPAT_DIR
     # Hop into themes directory.
     - cd $theme_dir
     # After CodeSniffer install you should refresh your path.
@@ -88,4 +92,4 @@ script:
     # -n flag: Do not print warnings (shortcut for --warning-severity=0)
     # --standard: Use WordPress as the standard.
     # --extensions: Only sniff PHP files.
-    - $WP_DEVELOP_DIR/php-codesniffer/bin/phpcs -p -s -v -n . --standard=./codesniffer.ruleset.xml --extensions=php --ignore=*/woocommerce/*,*/src/*
+    - $PHPCS_DIR/bin/phpcs -p -s -v -n . --extensions=php --ignore=*/woocommerce/*,*/src/*