Add regexp support for template aliases
Add docs about regexp matchin in aliases
Fix file format to prevent regexp trouble

The file format of the templates and aliases files could previously contain
comments trailing a relevant line. This might have caused problems with regular
expressions containing a pipe character (which is used as an alternative in
regexp).
To prevent this, lines may now only consist of exactly two parts, divided by a
single pipe character (and some optional whitespace). In the templates file, the
split will be done left-oriented, in the aliases file right-oriented, and each
time with a maxsplit parameter of 1, so that any regexp will be left alone.
Implement regex replacing for extracted strings
Merge branch 'regex'

Implement regular expression support for the elements selected by STR_SPECs.
These need to be specified with additional switches.
Closes #1