Verify or Add Support for long double Types

[ameily]

Issue trailofbits/binrec-prerelease#87 added support for 32bit (float) and 64bit (double) types. C has a 80bit floating point type, long double, that is analogous of the 80bit FPU registers. We should either verify that binrec_lift supports the long double type or add support for it, which will most likely be very similar to how float/double support was added in trailofbits/binrec-prerelease#93.

[ameily]

This may be blocked until we have trailofbits/binrec-prerelease#101 fixed since I am unaware of any libc API that returns a long double.