Natural whitespace handling for SBT configuration parser AKA 'no more blankies'

The idea is to remove limitation with blank lines in sbt file.

For backward compatibility only one method is modified -  EvaluateConfigurations.splitExpressions.
Most pull request contains test and sbt files.
The father of idea is  @gkossakowski, solution was implemented by @WarsawScala members in project https://github.com/WarsawScala/sbtchallenge
When I saw that comment, I went, Hey I read that SO question!  I also tried/failed to come up with a helpful suggestion.  In the past, folks have joked about adding a char of text, reparsing until something changes. Anyway, it's fun to see SO in the wild.