reverting decoupling of NumberHelper from safe_join and adding tests for escaping of delimiters and separators

Introduced in 0f848dd5.

Fix NumberHelper options wrapping to prevent verbatim blocks being rendered instead of line continuations.  While I'm at it, wrap long comment lines consistently.

When a locale file sets the format of the positive
currency value as '%n %u', the default negative
currency format should be '-%n %u'.

Came with this one-liner for this:

    find . -name '*.rb' | \
    xargs chardet | \
    grep -v ascii | \
    cut -d: -f1 -s | \
    xargs -n1 ruby -0777 -ne 'puts $FILENAME if $_ !~ /#.*coding:\s*utf/i'

Welcome $_.

fixes an issue with number_to_human when converting values which are less than 1 but greater than -1 [#6576 state:resolved]
Signed-off-by: NSantiago Pastorino <santiago@wyeworks.com>

This reverts commit 006ec77e.

Signed-off-by: NAndrew White <andyw@pixeltrix.co.uk>