Add IMG tag and fix QR tag

[deckyfx]

What it is?

• I add IMG tag so now it can print an image using command inside the design instead of using the API method the syntax is {IMG[file://image/path/file.png]}
• Fix the QR and IMG TAG so it can be mixed with other TAG in a line in design, eg: {QR[data]}{C} will print the QR Code centered

Note:

• This is my first time requesting pull to another repo, so I don't know the guideline to do it, please kindly notify me if there is something I miss.
• you may ignore all changes but *.java files, I use the latest Android Studio and XCode, so you might be no need for those files.

Suggestion:

• Need a way to freely customize QR and IMG size printed

[leesiongchan]

Hi @deckyfx thank you for your PR! But can you exclude all the extra changes that aren't relevant to the PR? Like the gradle, package.json and more.

[deckyfx]

I see, ok, i will make a new PR later thank you