Unsafe `GetInt`, `GetBool`, `GetFloat`, and `GetDouble` leading to potential buffer overruns

[adriengivry]

Description

The current implementation of our GetInt, GetBool, GetFloat, and GetDouble functions is unsafe.

This has been partially addressed by #640 which proposed a workaround for the GetInt which is currently being used, and therefore required immediate attention.

This issue has been addressed on baregl (modern OpenGL wrapper) by this PR: adriengivry/baregl#10

Expected Solution

We need to provide a way to specify the buffer size, while providing ways to retrieve single values, arrays, and add support for indexed get parameters.

[adriengivry]

Fixed by #824