Real number boost amounts

Hi,
I've started using Goggles and they **exceed my expectations**. They really give me a way to escape what is imposed by the "one size fits all" approach. **Thanks.**

In applying reranking offsets I'd like to use real numbers instead of integers.
For example: "_/SomeDetail$boost=3.54,_"
Instead of "_/SomeDetail$boost=4,_"

I tried that and the syntax checker doesn't accept it.

**I suggest that boost or demotion amounts of real numbers would be useful.**

My use of that might not need more than 3 extra digits of precision, like 3.141.

Start by locating the syntax checker and the code that parses boost or demotion amounts. Try the example `_/SomeDetail$boost=3.54,_` and compare it with the existing integer form; done means valid real-number amounts are accepted with the requested precision.

Written by the indexing model from the issue text.