add header and trailer in each source file

add standard copyright header
add vim hints trailer
add the source code decorator script

used in commit ab1f3cdf719fe6e8f7a8bce51edb37fb840cef3d
to decorate the source files.
add usage instructions for cdeco.py
Merge branch 'develop' into feature/buffered-io

Conflicts:
	src/httpresponsewriter.c
	src/httpresponsewriter.h
Added haders and footers to httpresponse.{c,h}