Remove 'using namespace std' statement. Fixes #276 #469

	#
	# Copyright (c) 2022 ZettaScale Technology
	#
	# This program and the accompanying materials are made available under the
	# terms of the Eclipse Public License 2.0 which is available at
	# http://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
	# which is available at https://www.apache.org/licenses/LICENSE-2.0.
	#
	# SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
	#
	# Contributors:
	# ZettaScale Zenoh Team, <[email protected]>
	#
	name: emscripten

	on:
	push:
	branches: [ '**' ]
	pull_request:
	branches: [ '**' ]

	jobs:
	build:
	name: Build on ${{ matrix.os }}
	runs-on: ${{ matrix.os }}
	strategy:
	fail-fast: false
	matrix:
	os: [ubuntu-latest]
	steps:
	- uses: actions/checkout@v4
	- uses: jwlawson/[email protected]
	- uses: mymindstorm/setup-emsdk@v12
	- name: Compile debug
	run: \|
	mkdir build
	emcmake cmake -E env CFLAGS="-DZ_FEATURE_LINK_WS=1 -DZ_FEATURE_LINK_TCP=0 -DZ_FEATURE_LINK_UDP_MULTICAST=0 -DZ_FEATURE_LINK_UDP_UNICAST=0 -DZ_FEATURE_SCOUTING_UDP=0" cmake -DBUILD_SHARED_LIBS=OFF -DCMAKE_C_STANDARD=11 -DBUILD_EXAMPLES=OFF -DCMAKE_BUILD_TYPE=Debug -DBUILD_TESTING=OFF -DBUILD_MULTICAST=OFF -DBUILD_INTEGRATION=OFF -DBUILD_TOOLS=OFF -DZENOH_DEBUG=3 -H. -Bbuild
	make -C build

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