Complete the unit testing and add some features

[peter279k]

First of all, thank you for your great package. Let me access OpenWeatherMap API with PHP easily.

Change log

• Complete the unit testing.

• Ignore testing the getWeatherHistory method in OpenWeatherMap.php.
  This method is ignored because the api key need to have a paid permission.

• Integrate the integTests with tests.

• Replace sprintf function with str_replace in Weather.php because the character %s is proper for using the sprintf.

• Replace json_last_error_msg with json_last_error in OpenWeatherMap.php. Because the json_last_error_msg is available for PHP 5.5+ (see this link). In order to be compatible with older PHP version (like 5.3 or 5.4), so we do this.

• In ExampleCache.php, adding setTempPath method allow us to specify the cached file path.

• Using the # to comment message is deprecated in *.ini file. Replace the # with this ;.

• Set the proper configuration in phpunit.xml.dist file.

• Add the required extension: ext-curl in composer.json.
  It will check whether the curl extension is installed during running the Composer installation.

• Add the require-dev key in composer.json.

the travis-ci result
the testing code coverage report (provided by codecov)

[codecov-io]

Current coverage is 97.82% (diff: 100%)

No coverage report found for master at dadc126.

Powered by Codecov. Last update dadc126...fd923d7

[peter279k]

Hi @cmfcmf , I fix the icoUrl variable error.

[cmfcmf]

Hey @peter279k,
thank you for your contributions! I've gone through most of your changes now and only found a few minor issues which I have already fixed myself. Expect your changes to be merged soon!

[cmfcmf]

Why did you add this?

[peter279k]

Hi @cmfcmf , I didn't add this.
When I pull your repo, it automatically add this.Perhaps I don't remember to add this.
When I remove this code, some error will happen during unit testing.

Hi @cmfcmf , thank you for your comment.
Finally I found where the problem is. I will remove this later.

[cmfcmf]

This has been merged as part of #96. Thank you @peter279k!