Revert back to using __visc__init and cleanup without arguments. That is, they are no more DFG specific, rather just hints for compiler to insert compilation code

(1) Working on implementation of further lowereing the visc api by breaking the
DFG launch call into init, launch, wait, cleanup. There are issues pending when
these require some kind of inter procedural analysis to link init, launch, wait
and cleanup. This is necessary during code generation.
(2) Also contains changes which simplify GenVISC pass by using macro for
identifying various source __visc__ calls

(2) Modified parboil script to run each test multiple times based on
configuration

(2) Added dummy function calls for visc initialization and visc clean up to
benchmarks and added support for it to all the passes.
(3) Timers are now only printed once
(4) Added extra timers to parboil header file

(1) Removed a bug from parboil driver, where contentList of Directory objects was being shared among all objects. Added routine to options.py to run all valid visc benchmarks

pthread creation overhead added

global variable s for timers.

    This would help to use timers in any pass
(2) Added a command line argument -visc-timers to DFG2LLVM X86/NVPTX passes to
    turn on/off timers based on the command line argument
(3) Added stencil makefile which was missing till now from repo
(4) DFG2LLVM_NVPTX uses timers now

(2) Changes to Makefile of passes to ignore C++11 warnings

Not working: kernel includes image types, which is not supported in VISC.