Added CObjError, cosmoV_throw(), pcall(), and cosmoV_printError()

Errors are now handled very differently, parser errors and VM errors are now treated the same.
When cosmoV_error is called, cosmoV_throw is also called, which formats the error object and sets the panic state.
state->error now points to the latest CObjError when state->panic is true. To get a nice formatted Objection message, use
cosmoV_printError() and pass the state->error. pcall() was added to the standard base library. When called, the first argument
passed is called with the subsequent arguments given. If the call completed successfully, `true`,`nil` is returned. However
when an error occurs during the call, `false`,`<error>` is returned. Simply print the `<error>` to retrieve the error string.

src/cstate.h

@@ -37,6 +37,7 @@ typedef struct CState {
     int frameCount;
 
     CObjObject *protoObj; // start met obj for all objects (NULL by default)
+    CObjError *error; // NULL, unless panic is true
     CObj *objects; // tracks all of our allocated objects
     CObj *userRoots; // user definable roots, this holds CObjs that should be considered "roots", lets the VM know you are holding a reference to a CObj in your code
     ArrayCObj grayStack; // keeps track of which objects *haven't yet* been traversed in our GC, but *have been* found