Fixed Parser not handeling "FilesOnly" restriction, refactored module_t struct

Fixed Parser not handeling "FilesOnly" restriction

• when parsing and appending nodes to nodes the nodes now check if they are allowed to accept another pipe or not

refactored module_t struct

• extracted members of module_t that describe the allowed connections: numIn numOut and restrictions
• created new struct module_restrictions
• added new struct to Node and module_t
• added getter for the module_restriction members in module_t
• added getter for module_t members
• fixed code that relied on direct access to the module_t members

added tests for FilesOnly restriction fixed a bug where the number of open brackets were not correctly reset after the parser ran