Add project description files

grammar.txt — defines the grammar of my language
readme.txt — describes the language’s features and capabilities (at
time of final submission in early December)
Simply folder tree

Got rid of unnecessary “environment/” folder level in repository (a
remnant of the original project).
Add lexeme, lexer, and types modules
Add parser and trees modules
Add evaluator and environment modules
Add function-evaluator and loader modules
Add built-ins and built-in-types modules
Add runner module and makefile
Merge branch 'master' of https://github.com/kerned-code/dpl-403