Param syntax parser

[Dominik Marczuk]

The macro now has a fixed params syntax. It should be possible to define own syntax and possibly provide one or two predefined options.

Proposal:

1. Create a ParamParserInterface defining a parse() method
2. Create a QueryStringParamParser transforming the params just as it does now (using parse_str).
3. Create an XMLAttribParamParser transforming params as if they were attributes on an XML tag.
4. Inject the parser into uMacro ctor.

[Dominik Marczuk]

Done & merged to master