feat #681 Add support for the Hebrew language

This commit adds resource files for the Hebrew language.

Additionally, as in Hebrew using substring to produce the short day
name from the full day name does not work (because all days start
with the same letters), this commit adds the ability to define a
custom short name for days and months. If there is no custom short
name in a resource file, the default mechanism with substring is used.

Close #681

(cherry picked from commit ae05348e00f937dbd65df4729d2c3851df050376)