Put /build & /data into .gitignore
Add NEWS documentation
main.ld: slight tweak syntax
implement bitmap to save allocation check memory
implement object-pool to help checking resource usage
event: adapt to object-pool
Rearrange config macros
make: fix linker script is not in dependencies
bitmap: Add a macro to declare bitmap
event: use bitmap to record pending to reduce memory usage
file: Declare file data explicitly instead of untyped memory pool to check memory usage
tty out: Hang if fd is invalid
git: hide build and data
gdb: move gdb.txt to build/
task-stat-hook: provide hook function for debugger
task: add fields for dynamic stack size
move serial codes from kernel.c to serial.c
stack: wrap stacks as object pool
stack: enable dynamicly setting stack size
adapt to variable size stack