add for loops to parser / AST

Conflicts:
	compiler/parser.mly
parsing

Conflicts:
	compiler/ast.mli
	compiler/ast_printer.ml
	compiler/parser.mly
parsing
got parsting working
Semantic checking of control flow, if and while.
While loops and and if else statements are working.
GCD working
Merge remote-tracking branch 'origin/master' into control_flow

Conflicts:
	compiler/ast.mli
	compiler/ast_printer.ml
	compiler/generate.ml
	compiler/parser.mly
	compiler/sast.mli
	compiler/semantic_check.ml
	compiler/translate.ml
Update while_count.rapid
fixes
Merge branch 'control_flow' of https://github.com/rapid-lang/rapid into control_flow
Merge pull request #113 from rapid-lang/control_flow

Control flow