redesign of the network interface

• using async tasks to check the network device

rename kernel target

• fixed bug in the CI

revise code to increase the readability

• update several crates

Use stabilized `hint::spin_loop` instead of deprecated `atomic::spin_loop_hint`

• using the latest version of the crate x86

switch to the latest version of the nightly compiler

v0.3.47

switch to the latest version of the nightly compiler

add network driver for the Realteck device 8139

• Fix broken rdrand implementation (#154)
• revise VGA interface (#153)
• add network driver for the Realteck device 8139 (#150)
• add option to disable SMP support (#142)
• using a exponential backoff to realize a spinlock (#131)

add option to disable FSGSBASE support

• add option to disable FSGSBASE support, which is required on older x86 processors
• using a exponential backoff to realize a spinlock
• disable interrupts during the initialization of PCI devices => avoids a deadlock during the initialization of PCI devices

performance improvements

• revision of the memory subsystem initialization to avoid false sharing
• using a exponential backoff to realize a spinlock
• improving the performace of basic functions (e.g. memcpy)

required changes to support the latest nightly compiler

• required changes to support the latest nightly compiler
• using compiler builtins to realize basic operation (e.g. mercoy)

add function to determine the current priority of a task

v0.3.42

add system call to determine the priority of a task