(cherry picked from commit b2af67a9)

(mvc) remove previous sample from codebase, the helloworld plugin covers more. leave template sample in place, because it provides some additional options of the framework.

(cherry picked from commit a3e5de62)

(legacy) replace time with microtime in make_config_revision_entry, not needed for the config revision anymore because that method uses it's own timestamp. Revision entries are also used on some other config items, like firewall rules.

(cherry picked from commit 19a5fc38)

(cherry picked from commit 1311f7a8)

(cherry picked from commit 9d6d609f)

(cherry picked from commit 5678e118)

(cherry picked from commit db0ddb34)

(cherry picked from commit 61aaa61d)

(cherry picked from commit ef787b91)

(mvc) add default config revision if none is given, fix for https://github.com/opnsense/core/issues/386

(cherry picked from commit 11913af8)

(cherry picked from commit df22b6dc)

(cherry picked from commit 415c6092)

(cherry picked from commit 7bff127c)

(cherry picked from commit d516b8f4)

Leave out the submenu changes for now.

Discussed with: ad@

(cherry picked from commit 782276c2)

(cherry picked from commit df3deae0)

(cherry picked from commit 926b6ba9)

(cherry picked from commit 8f84ee17)

(cherry picked from commit f3c7dadf)

(No actual changes.)

o comment blocks filled arrays disappear
o empty array tags disappear
o empty value tags collapse

This only leaves comment blocks in empty tags, which create
whitespace noise, which fucks up the config.xml real bad,
rippling through to the code that deal with is_array, isset
and actual = array() assignments to fix the faulty config.
Will clean this up one by one later.

(cherry picked from commit ed59098b)
(cherry picked from commit 20d24274)

(cherry picked from commit 043324f8)

Leave the rest of the changes from master out for the sake
of further testing...

Our new config system writes two spaces, so this makes it easier to
diff against the factory reset config.

Also enables French for 15.7.14.  :)

Submitted by: Calexium

Yay, thanks, Wallace!