add sample script: samples/userspace/pthread.kp

Signed-off-by: Jovi Zhangwei <jovi.zhangwei@gmail.com>
add KTAP-CFLAGS into .gitignore

Signed-off-by: Jovi Zhangwei <jovi.zhangwei@gmail.com>
install ktap.vim syntax file in `make install`

Also move all vim related file into vim/ directory

Signed-off-by: Jovi Zhangwei <jovi.zhangwei@gmail.com>