For Loop Conversion

Loop Converter Skeleton - array-step-1

Added a check to loop increments - array-step-2b

Added a check on the loop's condition expression - array-step-2c

Finished array matcher - array-step-2

Retrieved matched nodes - array-step-3

Analysis for array loop indices - array-step-4

Added checking for naming and variable scope

Added confidence level and count-only command line args

Added aliased variable elision

Added support for iterator-based loops

Added support for single-iterator loops which call end() repeatedly

Added support for converting array-like containers

llvm-svn: 162610