Update underlying color with setting alpha and opacity, and re-structure as library.

[TNorbury]

_color field inside of the TinyColor object is now updated when setting the alpha or opacity.

Added relevant tests.

Also updated an import inside of an already existing test while I was here.

closes #3

P.S. I also know that stuff is still getting set up, so lmk if ya need me to update my PR to work with lints or CI.

[JamesMcIntosh]

Hi @calvintam236, have you been in contact with FooStudio/Ricardo Mendieta about taking over management of the original repository?
Is this repo fork going to be published to pub.dev?

[WieFel]

Hi @calvintam236, have you been in contact with FooStudio/Ricardo Mendieta about taking over management of the original repository?
Is this repo fork going to be published to pub.dev?

@JamesMcIntosh we tried to contact them and waited for a while but they don't seem to answer.
We want to publish this on pub.dev, yes! ;)

[TNorbury]

merged in #5

[JamesMcIntosh]

Hi @calvintam236, have you been in contact with FooStudio/Ricardo Mendieta about taking over management of the original repository?
Is this repo fork going to be published to pub.dev?

@JamesMcIntosh we tried to contact them and waited for a while but they don't seem to answer.
We want to publish this on pub.dev, yes! ;)

Thanks Felix, I've sent @mendieta an email at FooStudio and a message on Linked-In too, he's definitely still around as he's committing almost daily to private repositories on GitHub...

[calvintam236]

@TNorbury @WieFel Since null safety PR is still not yet here, let’s merge this and get the example project up to date as well.