Add initial implementation of poll function

.gitignore

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+node_modules
+coverage

README.md

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+# poll
+
+A simple poll function based on async, await, and an infinite loop.
+
+
+
+## Table of contents
+
+- [Installation](#installation)
+- [Tests](#tests)
+- [Documentation](#documentation)
+- [Usage](#usage)
+
+
+
+## Installation
+
+Install the NPM package as a dependency …
+
+```sh
+npm install --save poll
+```
+
+… and import it like this:
+
+```node
+const poll = require('poll');
+
+function fn() {
+  console.log('Hello, beautiful!');
+};
+
+poll(fn, 1000);
+```
+
+
+
+## Tests
+
+In order to run the tests, clone the repository and run the following commands:
+
+```sh
+npm install
+npm test
+```
+
+
+
+## Documentation
+
+### Syntax
+
+```
+poll(function, delay[, shouldStopPolling])
+```
+
+**Parameters**:
+
+- **function**: Required. A function to be called every `delay` milliseconds. No parameters are passed to `function` upon calling it.
+- **delay**: Required. The delay (in milliseconds) to wait before calling the function again.
+- **shouldStopPolling**: Optional. A function indicating whether to stop the polling process. The callback function is evaluated twice during one iteration of the internal loop:
+  - After the result of the call to `function` was successfully awaited. In other words, right before triggering a new delay period.
+  - After the `delay` has passed. In other words, right before calling `function` again.
+
+  This guarantees two things:
+  - A currently active execution of `function` will be completed.
+  - No new calls to `function` will be triggered.
+
+**Return value**:
+
+None.

license.txt

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+The MIT License (MIT)
+
+Copyright (c) Philipp Rudloff
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.