License IRI under Apache-2.0

[jakubcech]

This PR changes the current GNU GPL license to Apache 2.0 license. We're standardizing our licenses across the IF to encourage businesses to help contribute to IOTA's development. The Trinity and Entangled projects are already using the Apache 2.0 license.

For this change to go forward, we need an acknowledgement from the current non-IF IRI contributors. Currently, there exist the following non-IOTA Foundation code contributors:

• [ ] @davassi
• [x] @legacycode
• [ ] @footloosejava
• [x] @viossat
• [ ] @alfredch
• [x] @bluedigits
• [x] @pinpong
• [x] @gjeee
• [ ] @ahab94
• [ ] @lhfbc
• [x] @kamaci
• [x] @pcwu
• [x] @sbialy
• [x] @nmeylan
• [x] @ovanwijk
• [x] @CodeMonkeySteve
• [x] @Johnny-Milkshakes
• [x] @zoran
• [ ] @romansemko
• [ ] @msrb
• [ ] @H3npi
• [x] @adriantombu
• [x] @attritionorg
• [ ] @eukaryote31
• [ ] @aliasaila
• [ ] @nurazhar
• [ ] @mark-bradshaw
• [x] @adrianziser

Could each of you please comment below this PR that you are happy with licensing your code under the terms of the Apache 2.0 license?

If you are, please comment similar to:

I hereby license my existing contributions to this project under the terms of the Apache 2.0 license.

If you're not happy with the license change, please reply with details in the comments. Thanks!

[merlinrabens]

I hereby license my existing contributions to this project under the terms of the Apache 2.0 license.

[viossat]

I hereby license my existing contributions to this project under the terms of the Apache 2.0 license.

[merlinrabens]

@jakubcech davassi is listed twice above :)

[legacycode]

I hereby license my existing contributions to this project under the terms of the Apache 2.0 license.

[sbialy]

I hereby license my existing contributions to this project under the terms of the Apache 2.0 license.

[zoran]

I hereby license my existing contributions to this project under the terms of the Apache 2.0 license.

[gjeee]

I hereby license my existing contributions to this project under the terms of the Apache 2.0 license.

[adriantombu]

I hereby license my existing contributions to this project under the terms of the Apache 2.0 license.

[kamaci]

Congrats on switching to Apache 2.0!

I hereby license my existing contributions to this project under the terms of the Apache 2.0 license.

[nmeylan]

I hereby license my existing contributions to this project under the terms of the Apache 2.0 license.

[ovanwijk]

I hereby license my existing contributions to this project under the terms of the Apache 2.0 license.

[adrianziser]

I hereby license my existing contributions to this project under the terms of the Apache 2.0 license.

[pcwu]

I hereby license my existing contributions to this project under the terms of the Apache 2.0 license.

[attritionorg]

I hereby license my existing contributions to this project under the terms of the Apache 2.0 license.

[pinpong]

I hereby license my existing contributions to this project under the terms of the Apache 2.0 license.

[Johnny-Milkshakes]

I hereby license my existing contributions to this project under the terms of the Apache 2.0 license.

[CodeMonkeySteve]

I hereby license my existing contributions to this project under the terms of the Apache 2.0 license.