Add missing class properties

Should define class properties before using them. These additional arguments were added in a7b8e7bf
Merge pull request #68 from johnkary/patch-1

Add missing class properties
Replace 'null' with empty string

Fixes #51
Fix CS, should fix #67
Fix doc
Fix absolute URLs not being generated when a scheme requirement is given
Merge pull request #77 from elnur/generate-absolute-fix

Fix absolute URLs not being generated when a scheme requirement is given
Add support for hosts
Merge pull request #78 from elnur/host-support

Add support for hosts
Support Symfony 2.3
Fix the order of installation options
Fix spelling
Remove the unneeded type attribute
Change Composer version format
Remove extra spaces
Remove unneeded quotes around JS objects properties names
Composer *since* Symfony 2.1
Merge pull request #79 from elnur/symfony-2.3

Support Symfony 2.3
Merge pull request #80 from elnur/doc

Various doc fixes
Switch to the single var pattern