Sort local/static/global/sbvalue variables by name

[nobodywasishere]

Fixes #688

[nobodywasishere]

It currently also sorts the registers, which isn't ideal. Can't figure out a way to sort everything but these - not very familiar with rust or this codebase.

[cmrschwarz]

The current sorting order reflects the order in which variables were declared. This is true for structs aswell as function scopes. I personally find that behavior much more convenient, as there is symmetry between the code and the variables window. It also means that when stepping forward the order doesn't change at all and new variables will be added at the bottom, where you don't have to 'search' for them at all. If you decide to change this, please make it configurable.