Prettier: support for specified files and glob mode

[axetroy]

close #424

Thanks to @dshubhadeep for #433

support specified files mix with glob

> deno run prettier/main.ts script1.ts script2.ts **/**/test.ts

This allows to directly specify a file to be formatted.

Before

> deno run prettier/main.ts test.ts
Formatting test.ts
Formatting fs/test.ts
Formatting fs/copy_test.ts
Formatting fs/empty_test.ts
...

After

only format the test.ts

> deno run prettier/main.ts test.ts
Formatting test.ts

/cc @kt3k

[kt3k]

otherwise looks good to me.

[ry]

LGTM