Simpler hidden-file handling

[denisdefreyne]

Nanoc currently has two ways of not handling hidden files:

• The data source excludes hidden files, unless they’re explicitly included in extra_files.
• Glob patterns don’t match hidden files (because Nanoc does not use FNM_DOTMATCH).

It might be possibly to simplify this:

• The data source includes all files (including hidden ones).
• There is a ignore /**/.* rule in the Rules file by default.

CC @moll

[moll]

I'm all for it! Saves having to list dot-files separately in data_sources:

data_sources:
  - type: filesystem
    encoding: utf-8
    extra_files:
      - "**/.htaccess"