Updates coverage-model

```
932295e Merge pull request #51 from blazetopher/submod_bumps
e81a841 Bumps all submodules to latest
f5b2288 Merge pull request #50 from lukecampbell/ion_functions
eb74ac8 Adds new submodule extern/ion-functions
4a7333f Merge pull request #45 from oceanzus/append_param
5a501ca Use 1.x bootstrap only
5d1dc8a Adds parameter exists check and test coverage.
56a7324 Adds test coverage for append_parameter.
6460eb6 Allows append_parameter after coverage creation
78e5a7e Removes noisy log statemtent Leftover developmental logging
statement causing lots of noise...removed
ffdadbf Merge pull request #49 from blazetopher/fix_valcache
5340154 Fixes rare issue with clearing of _value_cache
b626065 Merge pull request #47 from blazetopher/pd_bug_fix
93072b3 Fixes bug in ParameterDictionary
4f83027 Merge pull request #46 from blazetopher/valcache_tests
0151b0f Adds test for _value_cache; fixes bug in tests
24a6b3b Merge pull request #44 from blazetopher/func_mod_deps
20d5daa Adds module_dependencies; moves things to Abstract
```