File extension for wallets

[llorllale]

It is best if we assign a standard file extension to wallet files, like .z (my favorite), or maybe .zold.

Motivation
Standardizing filename extensions is a standard practice and is widespread. Users and developers alike have the expectation that applications load by default only files with extensions that they recognize.

Imagine for example the WalletsInDir example documented in the README for the java-api: the user just happened to have some random README.txt file in the same directory as his wallets then some error is likely to be thrown later on as the files are iterated and parsed.

[0crat]

@yegor256/z please, pay attention to this issue

[0crat]

@llorllale/z this project will fix the problem faster if you donate a few dollars to it; just click here and pay via Stripe, it's very fast, convenient and appreciated; thanks a lot!

[0crat]

Job #164 is now in scope, role is DEV

[0crat]

Bug was reported, see §29: +15 point(s) just awarded to @llorllale/z

[yegor256]

@0crat assign @pbenety

[0crat]

@0crat assign @pbenety (here)

@yegor256 The job #164 assigned to @pbenety/z, here is why; the budget is 30 minutes, see §4; please, read §8 and §9; if the task is not clear, read this and this; there will be a monetary reward for this job

[0crat]

Manual assignment of issues is discouraged, see §19: -5 point(s) just awarded to @yegor256/z

[0crat]

@pbenety/z this job was assigned to you 6days ago. It will be taken away from you soon, unless you close it, see §8. Read this and this, please.

[pbenety]

@0crat waiting for review #282

[0crat]

@0crat waiting for review #282 (here)

@pbenety The impediment for #164 was registered successfully by @pbenety/z

[pbenety]

@llorllale please close this isssue. The PR #282 was merged.

[llorllale]

@pbenety thanks

[0crat]

@ypshenychka/z please review this job completed by @pbenety/z, as in §30; the job will be fully closed and all payments will be made when the quality review is completed

[0crat]

The job #164 is now out of scope

[ypshenychka]

@0crat quality good

[0crat]

Order was finished, quality is "good": +38 point(s) just awarded to @pbenety/z

[0crat]

Quality review completed: +8 point(s) just awarded to @ypshenychka/z