Apply fixes from StyleCI (phpdotenv#317)

Refactored parser and validate names (phpdotenv#311)

Merge pull request phpdotenv#292 from andreybolonin/patch-1

add php 7.3 to travis

Merge pull request phpdotenv#277 from Korbeil/276-variable-values-sta…

…rting-with-are-being-converted-into-empty-strings

276 variable values starting with are being converted into empty strings

Added the list of environment variable declared inside the 'env' file (…

…phpdotenv#199)

Merge pull request phpdotenv#195 from vlucas/php71

Test on PHP 7.1

Various fixes

Merge pull request phpdotenv#172 from vinkla/patch-2

Update phpunit config

Tweaked git files

Moved brace onto new line