improve code quality

- take ExceptionStackFrames by value
- inprove the documentation

revise the code to increase the readability

- update several crate

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

release v0.3.46

- 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 the option to disable FSGSBASE support

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

add system call to determine the priority of a task

add function to block and to unblock a task

- add minor modifications to support the latest nightly compiler

revise allocator to support the latest version of libstd

add syscalls to create cryptographicly secure random numbers

- add syscalls to create cryptographicly secure random numbers #96
- add integration tests
- avoid deadlock when multiple cores are available #106

add dependency to the trait  for the implementation of spinlocks

remove dependency to the feature "nakes functions"

improve the performance of the network interface

improve performace, revise network interface

- reduce the FPU interrupts
- revise network interface to impove the performance
- safer allocation/deallocation of the stack
- activate LTO support

remove race during the initialization phase

fix link in Cargo.toml, revise README

minor improvements

- revise frequency detection
- remove dependency to lazy_static
- introduce CachePadded to avoid false sharing
- perform cargo-audit for crates with security vulnerabilities
- increase UTF-8 support

remove dependency to unaudit crates