Initial v2.0 version (for really reals this time)

[vlucas]

Changes made:

• Moved everything under a proper PSR-4 Dotenv namespace with a constructor, so usage is now:

$dotenv = new Dotenv\Dotenv(__DIR__);
$dotenv->load();

• Now loads immutable by default (will not overwrite existing ENV vars). You can use $dotenv->overload() to make them mutable
• Now supports only shell-style variable syntax, and no other alternate loaders
• Updated README file to match new sytnax, etc.
• Kept same required assertions and others from the original v2 branch

[sagikazarmark]

Shouldn't headline markup be consistent?

[vlucas]

It is consistent with the other headlines in the file. You can't do an h3 level heading without the hash in Markdown.