nghttp2: Add version 1.23.1

[Description][1]:

> nghttp2 is an implementation of HTTP/2 and its header compression
> algorithm HPACK in C.
>
> The framing layer of HTTP/2 is implemented as a form of reusable C
> library. On top of that, we have implemented HTTP/2 client, server and
> proxy. We have also developed load test and benchmarking tool for
> HTTP/2 and SPDY.
>
> We have participated in httpbis working group since HTTP/2 draft-04,
> which is the first implementation draft. Since then we have updated
> nghttp2 library constantly to latest specification and nghttp2 is now
> one of the most mature HTTP/2 implementations.

[1]: https://nghttp2.org/

nghttp2.be0

@@ -0,0 +1,85 @@
+#!/usr/bin/env beesh
+
+# BEE_VERSION nghttp2-1.23.1-0
+
+## this file was created by bee init and should be executed to build a
+## bee-package. (Additional hints are located at the end of this file.)
+
+###############################################################################
+## The source URL(s) define the location of the sources that will be
+## downloaded. Version variables may be used to simplify reuse of this bee-file.
+
+SRCURL[0]="https://github.com/nghttp2/nghttp2/archive/v${PKGVERSION}.tar.gz"
+
+###############################################################################
+## Add URLs/pathes to patch files to the PATCHURL array.
+## The sources will be patched in the order of the array.
+
+# PATCHURL+=()
+
+###############################################################################
+## Add filename patterns to the EXCLUDE array of files that should not
+## be added to you package but may be present in the image directory.
+
+# EXCLUDE+=()
+
+###############################################################################
+## Uncomment the next statement, if the software may not be able to be built
+## outside the source directory and needs to be built inside the source
+## directory.
+
+# build_in_sourcedir
+
+###############################################################################
+## bee cannot detect buildtypes specified in subdirectories.
+## Sometimes packages "hide" the real sources in a subdirectory named
+## 'src' or 'cmake' or ..
+## use 'sourcesubdir_append' to specify this directory if known.
+
+# sourcesubdir_append src
+
+
+###############################################################################
+## Change the default (auto-detected) steps to
+## extract, patch, configure/setup, build and install the software.
+## Make sure the mee_install function does install everything to the
+## image directory "${D}"
+
+#mee_extract() {
+#    bee_extract "${@}"
+#}
+
+#mee_patch() {
+#    bee_patch "${@}"
+#}
+
+#mee_configure() {
+#    bee_configure
+#}
+
+#mee_build() {
+#    bee_build
+#}
+
+#mee_install() {
+#    bee_install
+#}
+## by default this may be 'make install DESTDIR="${D}"'
+
+###############################################################################
+##
+## Additional hints:
+##
+## The name of this bee-file should follow the following naming convention:
+##     pkgname-pkgversion-pkgrevision.bee
+##
+## You may remove all comments as long as SRCURL[${PKGVERSION}] is set.
+##
+## Everything in this file will be executed in a bash environment.
+##
+## Build the package by executing
+##     './pkg-version-N.bee' or
+##     'beesh ./pkg-version-N.bee'
+##
+## see http://beezinga.org/
+##