Move ws_statement type into new file
Add function for initializing a statement
Add internal helper for appending and reallocating arguments
Add function for appending a direct argument
Add function for appending an indirect argument
Merge pull request #289 from neithernut/add-statement-assembly

Add statement assembly functions
Add logical.commands file
Add stubs for logical commands
Implement ws_builtin_cmd_logical_not()
Add implementation for ws_builtin_cmd_logical_and()
Add implementation for ws_builtin_cmd_logical_nand()
Add implementation for ws_builtin_cmd_logical_or()
Add implementation for ws_builtin_cmd_logical_nor()
Add implementation for ws_builtin_cmd_logical_xor()