Fix public_key default value in lexik_paybox.parameters parameter

The parameter lexik_paybox.public_key seems to never been used in services, default value is now defined before parameter registration for parameter lexik_paybox.parameters
fix base name of request form
conform urlencode to the RFC 3986
Merge pull request #40 from nykopol/url_encode_spaces

conform urlencode to the RFC 3986
Merge pull request #38 from nykopol/fix_form_name

fix base name of request form
Merge pull request #33 from Jihell/patch-1

Fix public_key default value in lexik_paybox.parameters
Merge branch 'master' into refactoring

Resolved conflicts:
	Paybox/System/Base/Response.php