Improvement: ignore strings where no translation is need

[muescha]

there some common strings where a translation is not needed, because there are some numbers or some common english abbreviations.

i would add an option to ignore some translations to they not count as "translation missing"

maybe:

• as a special key name
• or for example in a additional .i18nignore file ;)

but i don't know if always there is no translation needed or in some languages the abbreviations also translatet (i know from russian that it is common that the english words are not translated but written in kyrillic letters)