Extensive code cleanup of the expression command.

- Rationalized EvaluateExpression to remove a lot
  of nesting; also added comments to make it easy
  to find what's happening where
- Made ExecuteRawCommandString subcontract out to
  EvaluateExpression
- Minor logging improvements


git-svn-id: https://llvm.org/svn/llvm-project/llvdb/trunk@106703 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed