Apply PSR-2 to the project

[iwat]

1. Objective

This PR has nothing to do with business requirement. It reformats the code according to PHP Standards Recommendations #2 (aka. PSR-2)

2. Description of change

$ composer global require "squizlabs/php_codesniffer=*"
$ phpcs --config-set default_standard PSR2
$ phpcbf src/admin
$ phpcbf src/catalog

3. Quality assurance

🔧 Environments:

• Platform version: OpenCart 1.5.6.4
• Omise plugin version: Omise-OpenCart 1.4
• PHP version: 5.3.29

✏️ Details:

Simply test everything.

4. Impact of the change

Code reformatted.

5. Priority of change

High, or prepare for conflict.

6. Additional notes

No.

[guzzilar]

@iwat ✋ fyi, originally, the idea was to following the code standard on each of platform first. Then, if they (platform) doesn't define, use Omise standard, and if we don't define, then use PSR standard.

Something like, Platform > Omise > PSR.

in this case, for tab and new line method, the code had followed from these documents https://github.com/opencart/opencart/wiki/Coding-standards#indentation https://github.com/opencart/opencart/wiki/Coding-standards#new-lines