Do not use a single list for slim instruction creation

This makes it a lot easier to reason about Slim.
Initial refactoring of the slim statement.
Added extra scenario test for placeholder scenario's (no content)
script table: clean up scenario search code.
Extract the factory from Statement.
Cleanup in symbol assignment.
Merge pull request #1 from amolenaar/slim2

Code cleanup SLIM client side
Merge branch 'slim2' into slim_refactoring
Removed SlimTable.appendInstructions().
Refactoring of statements into instructions and execution/(de)serialization
Enhance table error formatting

Stacktrace is of no use for users.
remove SlimTable.constructFixture() (no args)

Lower inheritance dependency
Remove unneeded method SlimTable.makeReturnedValueExpectation()
added todo comments
Removed SlimTable.getChild().
Removed unused annotation from SlimSerializer
Move specific SlimTable.callAndAssign down.
Move comparator function to -Util class
Use Reponse objects instead of plain, formatted text.
Needs more work, just put the interface in place.
Moved colorize()