regression: CLI processing of globs

从 bin/httpsnippet 中的 CLI 入口点开始，使用 glob 命令针对 src/fixtures/requests/*.json 重现失败。跟踪参数的解析方式以及单个输入的处理方式，然后添加涵盖多个 glob 文件的 CLI 测试，并验证每个输入都会产生输出，而不是出现 unknown-arguments 错误。

The prior version of HTTPSnippet allowed processing of globs on the CLI as follows:

httpsnippet ./*.json --target node --client request --output ./snippets

$ tree snippets/
snippets/
├── endpoint-1.js
├── endpoint-2.js
└── endpoint-3.js

I wasn't aware of this prior functionality (and there were no tests covering it) so it was missed.

Shouldn't be too terrible to add back. Let's have some tests for it this time, too.

Reproduction steps

run the following:

./bin/httpsnippet src/fixtures/requests/*.json --target node --client unirest --output ./example

And it returns this input:

Unknown arguments: src/fixtures/requests/application-json.json, src/fixtures/requests/cookies.json, src/fixtures/requests/custom-method.json, src/fixtures/requests/full.json, src/fixtures/requests/headers.json, src/fixtures/requests/https.json, src/fixtures/requests/jsonObj-multiline.json, src/fixtures/requests/jsonObj-null-value.json, src/fixtures/requests/multipart-data.json, src/fixtures/requests/multipart-file.json, src/fixtures/requests/multipart-form-data.json, src/fixtures/requests/multipart-form-data-no-params.json, src/fixtures/requests/nested.json, src/fixtures/requests/query.json, src/fixtures/requests/short.json, src/fixtures/requests/text-plain.json

When it should, instead, process all of those files.