(cherry picked from commit 877ad265)

I know, gettext('2') et al looks stupid, but not having a complete
gettext() wrapping only leads to bugs later on...

(cherry picked from commit 358cfb02)

(cherry picked from commit c00c5b3f)

(cherry picked from commit ec86345d)

(cherry picked from commit 4760cfda)

(cherry picked from commit 83554e53)

(cherry picked from commit d8946545)

Also inline the tab function while there.

(cherry picked from commit 8e3a78bc)

(cherry picked from commit 2df71ab1)

(cherry picked from commit 708a1d01)

(cherry picked from commit 735d0bed)

(cherry picked from commit 89c689b7)

(cherry picked from commit 9b8db233)

(cherry picked from commit 4453f751)

(cherry picked from commit 0246d65b)

Guess what's coming soon...  :)

(cherry picked from commit d4d6db27)

(cherry picked from commit 15da6558)

(cherry picked from commit 5b7c9fbd)

(cherry picked from commit 472a9143)

(cherry picked from commit bdf00a08)

(cherry picked from commit 41479a3d)

(cherry picked from commit 1a9e8c96)

(cherry picked from commit 3026a561)

(legacy) fix crashreport PHP Warning:  Illegal string offset 'rule' in /usr/local/www/firewall_nat.php on line 71

(cherry picked from commit 129def90)

(cherry picked from commit dd878efc)

This one and the former were good ideas, but:

o They only affected a very small percentage of the actual code, and
o Reviewing changes is best done in the config.xml, not the revision message.

(cherry picked from commit 808a2604)

(cherry picked from commit 31293e66)

(cherry picked from commit 19c90f70)

(cherry picked from commit e346cead)

We moved past a critical section with 15.7.18, so this no longer
has any operational value.  :)

(cherry picked from commit a1e44cc6)

(cherry picked from commit 2a60c252)