argparse version 1.0.0

[Andrey Zherikov]

Hi everyone,

I'm glad to announce first major version of 
[argparse](https://code.dlang.org/packages/argparse) - a library 
for creating command line interface. It took some time to figure 
out public API of this library and I believe it's mature enough 
for the major version.

If you don't know what argparse does, here is not complete list 
of features (see full list in 
[readme](https://github.com/andrey-zherikov/argparse#readme)):
- Positional arguments, short and long options
- Argument groups
- Subcommands
- Help text generation
- Shell completion