devel: add a config field to force dates to timestamp 0
Add a new config field named default-date under the devel section to force all
implicits date to a specific value. If a explicit date is passed, it will
override the default.
This patch only affect changesets. Other usages (blackbox, obsmarkers) are
updated in later patchs.
The test runner is setting a bunch of alias to force the '--date' argument. We
will replace theses aliases in a later patch.
$ rm -rf a
$ hg init a
$ cd a
$ echo a > a
$ hg ci -Am0
adding a
$ hg tag t1 # 1
$ hg tag --remove t1 # 2
$ hg co 1
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg tag -f -r0 t1
$ hg tags
tip 3:a49829c4fc11
t1 0:f7b1eb17ad24
$ cd ..