[user:name-raw] token checks in install should not be flagged as errors

The current dev release has added a check (per #1827980: Post module enable/disable requirements (README): Account settings - E-mails require manual update) to ensure that account e-mails have the [user:name-raw] token substituted for [user:name], so that username is still provided in welcome emails etc.

However, there are a fairly large number of sites which may be using both Real Name and other modules which may modify the registration/login process (e.g. Email Registration or LoginToboggan) to use identifiers other than the raw username. These sites may not want to include the [user:name-raw] token anywhere in the registration email, but instead use e.g. [user:mail]. The current approach prevents any changes to registration emails for such sites, unless the unwanted [user:name-raw] is added somewhere.

While understand don't want users installing the RealName module to end-up with misleading registration emails, at least those are fixable by correcting configuration, while the current resolution breaks existing functionality entirely. I'd like to suggest two modifications to the token verification:

1) The install checks are modified from REQUIREMENT_ERROR to REQUIREMENT_WARNING, and warning message modified, as they may not always be an error.
2) The admin settings form check is modified from a form_error to a warning message, to permit the email templates to be modified even if [user:name-raw] is not included in the template body, and the error message again modified.

Patch to follow...

Andrew