Refac function argument recording. fixes #25, #23 (#30)

* refac function call args, fixes #25 and #23

* support optional args

Author: domasx2

.ignore

@@ -0,0 +1,2 @@
+*.js
+*.js.map

dist/spec/index.test.d.ts

@@ -1,12 +1,13 @@
-declare class Dummy {
-}
-export declare class Example {
-    a: string;
-    c(arg1: string, arg2: string): string;
-    readonly d: number;
-    v: string | null | undefined;
-    received(stuff: number | string): void;
-    returnPromise(): Promise<Dummy>;
-    foo(): string | undefined | null;
-}
-export {};
+declare class Dummy {
+}
+export declare class Example {
+    a: string;
+    c(arg1: string, arg2: string): string;
+    readonly d: number;
+    v: string | null | undefined;
+    received(stuff: number | string): void;
+    returnPromise(): Promise<Dummy>;
+    foo(): string | undefined | null;
+    bar(a: number, b?: number): number;
+}
+export {};