Changes

Add Env/GenericParams overloads to various methods. (#1408)

* Add Env/GenericParams overloads to various methods.

These are needed for genericsTake2. They simply forward to the old
methods with null for now, which continue to exist (but deprecated), but the callers should all be updated, and so now
have more time to upgrade before the genericsTake2 branch is merged in
with the breaking changes.
(commit: 07433a0)

Reverse the order of the getBooleanValue parameters.
(commit: 4af691d)

Upgrade some call sites to non-deprecated versions
(commit: 760d39c)

Fix more deprecation warnings
(commit: 6d45acd)

Change 'environment' to 'env' everywhere
(commit: 45e9582)

Fix more deprecations
(commit: 3eadef1)

Merge additional changes from genericsTake2 to reduce the diff.
(commit: d4f8b9f)

Continue fixing deprecations
(commit: da2b820)

Refactor ObjectGenerator
(commit: 903f744)

Remove unneeded item() overload
(commit: e0e944c)

Upgrade MCTagType
(commit: 6d8759f)

Cherry-pick select changes from genericsTake2
(commit: 4bd4788)

Add .mvn folder to gitignore
(commit: f14c8e5)

Fix optimization issue in material_info
(commit: 689bc2b)

Also fix max_stack_size
(commit: f12d3ef)

Convert to an iterative eval loop instead of a recursive one (#1409)

* Convert to an iterative eval loop instead of a recursive one.

This is a major change in the script evaluation process, which changes
how "special execution" functions work. Previously, functions could
choose to implement execs instead of exec, which received a ParseTree,
instead of Mixed. This allowed the individual function to decide how or
even if the ParseTree nodes were further executed. This works in
general, however it has several drawbacks.

In particular, the core evaluation loop loses control over the script
once it decends into individual functions. Therefore features like
Ctrl+C in command line scripts relied on each of these "flow" functions
to implement that feature correctly, and only some of them did. This
also prevents new features from being implemented as easily, like a debugger,
since the evaluation loop would need to be modified, and every single
flow function would need to make the same changes as well.

This also has several performance benefits. Using a recursive approach
meant that each frame of MethodScript had about 3 Java frames, which is
inefficient. The biggest performance change with this is moving away
from exception based control flow. Previously, return, break, and
continue were all implemented with Java exceptions. This is more
expensive than it needs to be, especially for very unexceptional cases
such as return(). Now, when a proc or closure returns, it triggers a
different phase in the state machine, instead of throwing an exception.

This also unlocks future features that were not possible today. A
debugger could have been implemented before (though it would have been
difficult) but now an asynchronous debugger can be implemented.
async/await is also possible now. Tail call optimizations can be done,
execution time quotas, and the profiler can probably be improved.

* Use our own stack counter to determine when a StackOverflow happens.

* Add CallbackYield class for functions that execute callbacks.

Previously, callback invocations required re-entering the eval loop from
the top, which defeats the iterative loop. In principal,
the functions that call Callables need to become flow functions to
behave correctly, but for basic yield-style invocations, this
infrastructure is too heavy, so CallbackYield is a new class which puts
the function in terms of an exec-like mechanism, only introducing the
Yield object, which is just a queue of operations, effectively.

More functions need to convert to this, but as a first start, array_map
has been converted. Some of the simpler FlowFunctions might be able to
be simplified to this as well.

* Convert various function to CallbackYield functions.

These are the "easy" functions to convert.

* Finish converting CallbackYield and FlowFunctions
(commit: b846e13)

Unwrap CREs from the reflection exception
(commit: 1eb61de)