revisions to ocl probes
Added support for LIFRate (fixes #16?).
Made test_ast_conversion work again
Changes to make profiling easier.

- Also added benchmark_circconv for comparing simulators.
Added viewer for benchmark_circconv.
Added a new test for clra_gemv.
Fixes to clra_gemv test.

- can now reproduce dot_block_size == 0 in clra_gemv.many_dots_impl.
removed Timers
fix: ocl probe error
enh: small ocl probe optimization
Simplify Usage in README

- model.simulator passes **kwargs to Simulator constructor
Added Debian unstable installation
fix many_dots segfault
print out geometry in ref_impl
Changes to make profiling easier.

- Also added benchmark_circconv for comparing simulators.
Added a new test for clra_gemv.
Fixes to clra_gemv test.

- can now reproduce dot_block_size == 0 in clra_gemv.many_dots_impl.
Made AST conversion better.