Add rule to make delbrot

This allows people to build the interpreter without needing the FFmpeg or x264 libraries.
Merge pull request #7 from lukechampine/newlang

Add rule to make delbrot
first specification of lexing/parsing rules for new syntax
more support for booleans and various other tweaks
remove guards, add assert, make bools work
reorganize delbrot.h and support functions with no arguments
fix ternary operator, tweak scoping rules, and start implementing default
major improvements to optional argument handling
fix precedence and remove INC, DEC
fix comparison operators and properly define them for each type
add type conversion functions
add support for literals without initial 0 (e.g. .5)
update README and language spec
fix argument handling and add default fn return value
Update documentation
Fix rendering issues
fix chaining and change default syntax
call go() on EOF (eventually)
Update Readme
rewrite unit tests with new syntax