Convex Lisp Runner.

This is a whole application. It is available as a library in case it needs to be embedded. Then, only [[-main]] is really
useful.

Executes each form as a transaction, moving from transaction to transaction.

A transaction can return a request to perform operations beyond the scope of the CVM, such as file IO or
advancing time. Those requests turn Convex Lisp, a somewhat limited and fully deterministic language, into
a scripting facility.

Requests are vectors following expected conventions and implementations can be found in the [[convex.run.sreq]]
namespace.

A series of CVX libraries is embedded, building on those requests and the way the runner generally operates,
providing features such as reading CVX files, unit testing, a REPL, or time-travel. All features are self
documented in the grand tradition of Lisp languages.

Functions throughout these namespaces often refer to `env`. It is an environment map passed around containing
everything that is need by an instance: current CVM context, opened streams, current error if any, etc.

In case of error, [[convex.run.exec/fail]] must be used so that the error is reported to the CVX executing environment.

List of transactions pending for execution is accessible in the CVX execution environment under `$.trx/*list*`. This list
can be modified by the user, allowing for powerful metaprogramming. Besides above-mentioned requests, this feature is used
to implement another series of useful utilities such as exception catching.

Altering and quering informations about the CVM context attached to an env.

Errors are CVX maps, either mappified CVM exceptions or built from scratch.

Using [[convex.run.exec/fail]], they are reported back to the CVX executing environment
and can be handled from CVX.

This namespace provides functions for building recurrent error maps.

All aspects of actually executing transactions.

When an error is detected, [[fail]] is called.

Basic IO utilities and STDIO.

Text streams are meant for reading characters (`Reader` and `Writer`) while binary streams are meant to handle
raw bytes (`InputStream` and `OutputStream`).

CVX keywords used by the runner.

Implementation of requests interpreted by the runner between transactions.

A reqest is merely a CVX vector following some particular convention that the
runner follows for producing effects beyond the scope of the CVM.

Handling files and STDIO streams.

A stream is an id that represents an opened file or a STDIO streams. Those ids are kept in env.

All operations, such as closing a stream or reading one, rely on [[operation]].

Used for implementing IO requests.

CVX symbols used by the runner.