Before this commit, "lazy translated" strings were implemented as
objects with a toString function. This is simple, but does not emulate
very well the real behaviour of a string.
In this commit, we create a LazyTranslatedSTring class which subclass
the String class, so all string methods will work as expected.
We also expose the _t function here, to make it more convenient for some
code to access the translations instead of depending on the presence of
an environment.
Géry Debongnie
d4bbadd699