Add ability to set layout scripts block name in config

[sandric]

I moved scripts block name to config, because I think its a bad idea to hardcode block where should js be. For example if I want it to go in head or body, and I do not want to create another one in layout file. Or, lets say I actually do not have access to layout, lets say it is created by some factory code, like in active admin.

[apneadiving]

ok why not!

[sandric]

yeap!)