Add indents to AST dumping and removed parenthesis from AST nodes.
Indents were given the color blue when outputting with color.
AST dumping now looks like this:

Node
|-Node
| `-Node
`-Node
  `-Node

Compared to the previous:

(Node
  (Node
    (Node))
  (Node
    (Node)))



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@174022 91177308-0d34-0410-b5e6-96231b3b80d8