Wrap also correctly if no other module is required.
Merge pull request #2 from ep-ahartmann/fix/wrapping

Wrap also correctly if no other module is required.
Find AMDs.
Find CommonJS modules.
Fix: Find AMD and CommonJS modules also if 'module' or 'exports' are global program variables.
Detect also `exports` if it's used as a function parameter which often occurs in UMDs