* Makes the HAL provide a better error message for certain things.
* Makes Java error messages better
* Updates C++ errors.
* Moves handles header folder to HAL directory
Internally, the linked list now uses shared_ptrs instead of raw
pointers. In addition, in the WPILib the notifier handle is now made
atomic. Then before the class is destructed, the handle is now set to 0.
This should help solve one of the existing race conditions. A 0 handle
is correctly handled down at the HAL level.
Subsections are alphabetized according to lexographic ordering. Also, HAL includes were moved from headers to source files where possible. This change may cause user code which uses HAL functionality and does not include the relevant HAL header (since it may have been provided by another WPILib header) to fail to compile.
As the notifierMutex is unlocked while the callback is being called in
alarmCallback(), it's possible for next to be invalidated due to a
cleanNotifier() call. Now, instead of deleting the notifier immediately,
add it to a freelist to be cleaned up at the tail end of alarmCallback.
Rename the following folders:
hal/lib/Athena -> hal/lib/athena
hal/lib/Desktop -> hal/lib/sim
hal/lib/Shared -> hal/lib/shared
wpilibc/Athena -> wpilibc/athena
wpilibc/simulation -> wpilibc/sim
Windows users may need to run gradlew clean after updating.
