Italian translation improvements

[daghemo]

The italian translation may not be perfect in certain circumstances.

E.g., "* 0-7,19-23 * * *" would returns:

Ogni minuto, alle 00:00 al 07:59 e 19:00 al 23:59

I've used the following snippet:

import cron_descriptor
descripter = cron_descriptor.ExpressionDescriptor("* 0-7,19-23 * * *", use_24hour_time_format=True, locale_code='it_IT')
print(descripter.get_description())

The correct result should be:

Ogni minuto, dalle 00:00 alle 07:59 e dalle 19:00 alle 23:59

This can be obtained modifying the it_IT.po as follows:

# diff -ruN it_IT.po.orig it_IT.po
--- it_IT.po.orig       2019-01-17 11:24:15.033002345 +0100
+++ it_IT.po    2019-01-17 11:25:45.237514411 +0100
@@ -96,7 +96,7 @@
 #: ExpressionDescriptor.py:218
 #, python-brace-format
 msgid "at {0}"
-msgstr "alle {0}"
+msgstr "dalle {0}"

 #: ExpressionDescriptor.py:241
 msgid "first"
@@ -151,7 +151,7 @@
 #: ExpressionDescriptor.py:318
 #, python-brace-format
 msgid ", {0} through {1}"
-msgstr ", {0} al {1}"
+msgstr ", {0} alle {1}"

 #: ExpressionDescriptor.py:272
 #, python-brace-format
@@ -207,7 +207,7 @@

 #: ExpressionDescriptor.py:385
 msgid " and "
-msgstr " e "
+msgstr " e dalle "

 #: ExpressionDescriptor.py:433
 msgid ", every minute"

But I think that this would lead to errors in other circumstances (e.g. "0,30 6-17 * * *").
That's why using the "between {0} and {1}" syntax as follows should be a better option:

Ogni minuto, tra le 00:00 e le 07:59 e tra le 19:00 e le 23:59