…SoftwareFoundation#3555)

Just a couple missing pieces were preventing getattribute() from
retrieving attributes that were stored as int64 or uint64. That
doesn't come up very often, but one place is retrieving certain
statistics that use 64 bit counters. (This comes up in ImageCache,
among other places.)

While we're at it, there was no existing test dedicated to the python
binding of ImageCache. So to add these getattribute calls, I made one.

There is an important caveat about ImageCache.getattribute(): In this
process, I discovered that the flavor of IC.getattribute(name) where
you only pass the name is BROKEN, and will always return None. You
MUST use the form where you pass the type, like

    x = ic.getattribute("foo", "int")

This is unfortunate and not very Pythonic, but it is the workaround
for now. I will addess getting the name-only form working in a
separate PR.

Closes AcademySoftwareFoundation#3537

Changes since RC1:

  - ImageCache/TextureSystem both have added a `getattributetype()`
    method, which retrieves just the type of a named attribute. AcademySoftwareFoundation#3559
    (2.4.4.0)  NOTE: THIS IS AN ABI BREAKING CHANGE
  - Python: Fix the ability to `getattribute()` of int64 and uint64
    metadata or attributes. AcademySoftwareFoundation#3555 (2.4.4.0)
  - Build: Improvements to the generated cmake config files when
    building static libraries. AcademySoftwareFoundation#3552 AcademySoftwareFoundation#3557 (2.4.4.0)
  - Support for gcc 12.1. AcademySoftwareFoundation#3480 (2.4.2.1) AcademySoftwareFoundation#3551 (2.4.4.0)
  - Support building with clang 15.0. AcademySoftwareFoundation#3563 (2.4.4.0)
  - Fix cross-compiling on Android failing due to `-latomic` check. AcademySoftwareFoundation#3560
    (2.4.4.0)
  - Fix building on iOS. AcademySoftwareFoundation#3562 (2.4.4.0)

Changes since RC1:

  - ImageCache/TextureSystem both have added a `getattributetype()`
    method, which retrieves just the type of a named attribute. AcademySoftwareFoundation#3559
    (2.4.4.0)  NOTE: THIS IS AN ABI BREAKING CHANGE
  - Python: Fix the ability to `getattribute()` of int64 and uint64
    metadata or attributes. AcademySoftwareFoundation#3555 (2.4.4.0)
  - Build: Improvements to the generated cmake config files when
    building static libraries. AcademySoftwareFoundation#3552 AcademySoftwareFoundation#3557 (2.4.4.0)
  - Support for gcc 12.1. AcademySoftwareFoundation#3480 (2.4.2.1) AcademySoftwareFoundation#3551 (2.4.4.0)
  - Support building with clang 15.0. AcademySoftwareFoundation#3563 (2.4.4.0)
  - Fix cross-compiling on Android failing due to `-latomic` check. AcademySoftwareFoundation#3560
    (2.4.4.0)
  - Fix building on iOS. AcademySoftwareFoundation#3562 (2.4.4.0)

Note that we bumped the version to from 2.4.3.x 2.4.4.0 to reflect the
ABI break introduced by the last minute by the IC/TS addition of a new
virtual function. ABI will not change again for 2.4.