Split signature tests to a separate file
Fix Signature.Values for arrays of complex types
Add more tests and benchmarks
Convert []interface{} to appropiate structs in (*Call).Store
Add Store function behaving correctly for nested structs

The new function is a generalized form of (*Call).Store, working not
just on method calls, but on any slice of interfaces. This function
handles nested structs correctly.
Return correct alignment for maps in alignment()

This is just for completeness' sake, since maps were aligned correctly
anyway as their first element, an uint32, is aligned correctly.
Use provided pointer when decoding into a pointer
Append to provided slices when decoding
Mention arrays in the docs