Update proof tools (+disable submodule cloning by default) (#20)

This commit advances Litani to release 1.10.0, and the starter kit to
the tip-of-tree. This brings the following improvements:

- Profiling
    - Litani measures the memory usage of the CBMC safety checking and
      coverage checking jobs
    - The dashboard includes box-and-whisker diagrams for memory use per
      proof
    - The dashboard includes a graph of how many parallel jobs are
      running over the whole run, making it easy to choose a CI machine
      with enough parallelism
    - It is now possible to designate particular proofs as "EXPENSIVE";
      Litani runs expensive proofs serially, ensuring that they do not
      over-consume resources like RAM.

- UI improvements
    - Each pipeline page includes a table of contents
    - Each pipeline page includes a dependency graph of the pipeline
    - Each job on the pipeline page has a hyperlink to that job
    - The terminal output is now less noisy

.gitmodules

@@ -1,9 +1,12 @@
 [submodule "test/unit-test/CMock"]
 	path = test/unit-test/CMock
 	url = https://github.com/ThrowTheSwitch/CMock.git
+	update = none
 [submodule "test/cbmc/aws-templates-for-cbmc-proofs"]
 	path = test/cbmc/aws-templates-for-cbmc-proofs
 	url = https://github.com/awslabs/aws-templates-for-cbmc-proofs.git
+	update = none
 [submodule "test/cbmc/litani"]
 	path = test/cbmc/litani
 	url = https://github.com/awslabs/aws-build-accumulator
+	update = none

test/cbmc/.gitignore

@@ -3,6 +3,7 @@ proofs/**/logs
 proofs/**/gotos
 proofs/**/report
 proofs/**/html
+proofs/output
 
 # Emitted by CBMC Viewer
 TAGS-*