Rename pinkySim.c to pinkySimStep.c

Preparing to add more functionality to pinkySim while keeping the large
single stepping code separate in its own source file.
Update README to reflect pinkySim.c rename
Add pinkySimRun() support

This function executes instructions in memory until a significant
event such as a breakpoint, fault, etc occurs.
Rolled pinkySimRun.c back into pinkySim.c

Once I implemented pinkySimRun() I saw that it was pretty short so
there was no reason to split it away from pinkySimStep().

This commit also includes changes to pinkySimStepTest.cpp which I
forgot to add with my previous commit.