Ability to pass variables into lessphp filter

[kastaneda]

This is a very simple enhancement that lets pass variables into the less file from php (using the already existing functionality):
http://leafo.net/lessphp/docs/#setting_variables_from_php

I also concerned about the ability to set these variables from config.yml, this requires appropriate changes in AsseticBundle.

I suppose an example to call lessphp:

assetic:
    filters:
        lessphp:
            presets:
                baseColor:      '#f00'
                anotherColor:   '#0f0'
                imagePrefix:    'http://cdn.example.com/img/'

[stof]

most filters use setters for the options instead of constructor arguments

[kriswallsmith]

Yes, this should be a setter.

[stof]

@kastaneda can you update your code to inject the variables through a setter instead ?
And please also add a test for this feature

[stof]

@kastaneda ping