Convert "version" option to flag "-V,--version".

[ScottBailey]

Convert "version" option to flag "-V,--version". This is consistent with both GNU and defacto standards.

Some formatting was changed (removed trailing white space).

I don't think it's necessary to add a test for this flag.

Fixes #29

[mikelik]

I would expect the -v to work, but only -V works.

mikel@msi:~/repo/antler-proj/build/tools$ ./antler-proj -v
The following argument was not expected: -v
Run with --help for more information.
mikel@msi:~/repo/antler-proj/build/tools$ ./antler-proj -V
antler-proj v1.0.0

[mikelik]

I just learned that there are tools that support only case sensitive -V

[ScottBailey]

I would expect the -v to work, but only -V works.

Lowercase v flag (-v) often - in my experience - represents verbose setting (--verbose). I sampled a couple tools on my Linux install and saw uppercase V was a synonym for version. Given we may want to add a verbose setting later, the other option was the long flag (--version) only, but I think -V is a nice option.