Merge pull request #12 from lioncash/master

Some ternary statement fixes. Also a boolean expression simplification.
Mirco-opt: Rewrote string concatenation to StringBuilder use - fixed #14
[Micro-opt] Fixed #13 possible infinite loop
Compress some properties within AbstractNode.cs into auto properties. Makes the class look a little neater.
Fix three parameter names in the exception throws in DFormattingVisitor.cs.
Add the flags attribute to the Inside enum in IndentStack.cs, since it's used like the entries are a bunch of flags. Also vertically aligned them all.
Compress some for loops into foreach loops in situations where readability can be improved.