Feature/argon2 contexts secret and associated data

[suniastar]

I've added some advanced hash and verify methods to support argon2's secret and associated data.
I needed this for one of my projects and also saw issue #83.

Added:

• Argon2_context Structure Class as the representation of its C struct.
• Argon2_version as a better representation of its C counterpart.
• The C argon2*_ctx(argon2_context *context); methods to Argon2Library class.
• 2 rawHashAdvanced and verifyAdvanced methods to Argon2Advanced because the argon2*_ctx(argon2_context *context); methods do not encode the hash.
• Also callLibraryContext and callLibrarayVerifyContext methods to BaseArgon2, Argon2i, Argon2d, and Argon2id to support the new native library calls.
• Minor private helper methods in BaseArgon2.
• Some tests for the new methods.

Modified:

• JavaVersion from 1.6 to 1.8 as my gradle wouldn't compile the project otherwise.
• Argon2Version to fit the new Argon2_version JnaUint32 class.

Testing:

• I've tested the new methods with the added tests but only on a Linux x64 machine (running ArchLinux) and they worked so far.

As this is one of my first real Github contributions feedback is much appreciated.

[suniastar]

BTW, is there a reason for the current java target and source version 1.6?

[suniastar]

I don't know why but there seems to be an issue with the mac Github checks.
Only a few lines of code where changed with my last commit but the tests seem to be stuck or don't provide an error message.

EDIT: Seems to be a temporary issue. All checks after the last commit passed.

[phxql]

Wow, thanks for that contribution! I'm gonna take a look and test it.

Regarding to Java 1.6: That was done to support Android, afaik they need 1.6 bytecode.

[suniastar]

Should I revert it to 1.6 in this case or will you do it as part of your review?

Just FYI: Android uses 1.6 bytecode by default but most developers (incl. Google) suggest setting target and source compatibility to at least 1.8 in order to support all API features.
https://developer.android.com/studio/write/java8-support

[phxql]

Should I revert it to 1.6 in this case or will you do it as part of your review?

Just FYI: Android uses 1.6 bytecode by default but most developers (incl. Google) suggest setting target and source compatibility to at least 1.8 in order to support all API features.
https://developer.android.com/studio/write/java8-support

I would prefer to stay on 1.6 just to be on the safe side. What's the problem with 1.6?

I added some comments to your changes, please review. And thanks again for your contribution, it's great!

[suniastar]

Thanks for the review. I've adjusted the things we discussed in the conversations.
Please take a look.

Let me also give you some praise for your dedicated work.
Not every reviewer/project owner would have seen that I accidentally swapped the java doc for argon2i_ctx and argon2d_ctx.

[phxql]

Thank you! I've merged it into develop branch :)