Script instance as struct

[gilzoide]

This PR changes script and script instances to be structs, to maintain a more consistent behavior regarding the call of property getters and setters in __index and __newindex metamethods (#5). To bypass getters and setters, use rawget and rawset.

It also:

• Adds mapping for Server platform, using the linux_x86_64 build. This is necessary to run the automated tests in CI.
• Adds debugger.lua submodule to trigger breakpoints when automated tests fail
• Fixes Array/Pool*Array __eq metamethod to not raise when comparing against primitive Lua values
• Fixes support false as a default value for properties
• Changes Object.call to raise in case of errors, instead of failing silently. Use Object.pcall to protect calls instead.