## Summary of the Pull Request
<!-- Please review the items on the PR checklist before submitting-->
## PR Checklist
* [x] Closes#4013
* [x] I work here.
* [x] Existing tests should be OK. Real changes, just adding a lib to use.
* [x] Couldn't find any existing docs about intsafe.
* [x] Am core contributor.
## Detailed Description of the Pull Request / Additional comments
* [x] Can we remove min/max completely or rename it in the two projects where it had to be reintroduced? This is now moved into #4152
* [x] How many usages of the old safe math are there? **79**
* [x] If not a ton, can we migrate them here or in a follow on PR? This is now moved into #4153
Files with old safe math:
- TerminalControl: TSFInputControl.cpp
- TerminalCore: TerminalDispatch.cpp
- TerminalCore: TerminalSelection.cpp
- Host: directio.cpp
- RendererGdi: invalidate.cpp
- RendererGdi: math.cpp
- RendererGdi: paint.cpp
- RendererVt: paint.cpp
- TerminalAdapter: adaptDispatch.cpp
- Types: viewport.cpp
- Types: WindowUiaProviderBase.cpp
## Validation Steps Performed
For our Universal terminal for development purposes, we will use telnet to escape the universal application container and empower developers to debug/diagnose issues with their own machine on loopback to the already-elevated telnet context.
Switch to using jsoncpp as our json library. This lets us pretty-print the json file by default, and lets users place comments in the json file.
We will now only re-write the file when the actual logical structure of the json object changes, not only when the serialization changes.
Unfortunately, this will remove any existing ordering of profiles, and make the order random. We don't terribly care though, because when #754 lands, this will be less painful.
It also introduces a top-level globals object to hold all the global properties, including keybindings. Existing profiles should gracefully upgrade.
