Added url.js to tmp repo
Started to fix the problem with updating search param
Comments and new private functions
Simplified addSearch function

Parse query, search param in parsed object, update the parameter and
then just stringifiy the object. Finally, we can replace the current
state of history.
addSearch --> updateSearch
Renamed function: updateSearchParam
Handle no value -> delete
Updated comment
Fixed delete param computing. Other minor fixes

Delete "?" when there are not any parameters to stringify.
Added TODO
Merge branch 'master' of ../url