Moves parser into separate sub-package, to make room
for other components.
Implements Number.Parse() method. Converts numeric literal
into float64 or int64.
Adds LANGUAGE.md which defines some basic language
specification details.
Begins extending the AST type with syntax verification code,
as well as the Expand() method. The former is invoked
by default as the last stage of the Parse() procedure.

The latter is called manually. It will expand compact
definitions like `let` into multiple, nested definitions.
Implements Char.Parse method.
IImplements more syntax validation and preparation
for syntax expansion of let and define statements.
Refactors some of the expansion and syntax verification code.
Amends README with information about source expansion.
Further imlpements syntax verification and expansion code.
Modifies test cases to ensure they work as intended.
Moves statement expansion information from README to LANGUAGE file.
Further documentation additions and revisions.
Removes notion of quoted list from lexer.
The quote atom or single quote (') is now lexed as
an atom and should be handled later on. We will be
allowing quotation of any expression.
Adds more syntax verification code.
We currently ensure the validity of `let` statements as well as
`define` statements. Both as a single variable define, or the
procedure short-hand form.
Imlpements more syntax verification and associated tests.