build
adding user agent in curl calls for downloading dependency
Merge branch 'v2.3.101' into stable
Merge branch 'stable'
Moving sdk_config.ini to samples folder and updating installation script / README.md
Update README.md
Updating installation instructions in README.md
Update composer.json
Merge remote-tracking branch 'origin/master' into namespace-php5.3

Conflicts:
	composer.json
	lib/PayPal/Service/InvoiceService.php
	lib/services/Invoice/Invoice.php
	samples/composer.json