Implement FILEMAN:Unzip(string zipPath, string targetPath, int strip)

Unzip zip file at `zipPath` to `targetPath`.
`strip` is optional and defaults to `0`. If set to a number larger than
`0`, that many components are removed from the paths of the extracted
files. e.g. `a/b/c` is replaced with `b/c` when stripping one component
or just `c` when stripping two.
Returns whether all files were extracted successfully.

Docs/Luadoc/Lua.xml

@@ -1596,6 +1596,7 @@
 			<Function name='GetDirListing'/>
 			<Function name='GetFileSizeBytes'/>
 			<Function name='GetHashForFile'/>
+			<Function name='Unzip'/>
 		</Class>
 		<Class name='RageInput'>
 			<Function name='GetDescriptions'/>